Method and device for performing SL communication in NR V2X on basis of auxiliary information

ABSTRACT

Provided are a method for a first device to perform wireless communication and a device supporting same. The method comprises the steps of: receiving an auxiliary information request from a second device; generating auxiliary information on the basis of the auxiliary information request; transmitting first sidelink control information (SCI), including scheduling information about a physical sidelink shared channel (PSSCH), to the second device through a physical sidelink control channel (PSCCH), wherein the first SCI includes information related to frequency resource allocation, information related to time resource allocation, information related to a demodulation reference signal (DMRS) pattern, and information related to a modulation and coding scheme (MCS); and transmitting the auxiliary information to the second device through the PSSCH in response to the auxiliary information request, wherein the auxiliary information may include information for sidelink (SL) resource selection for the second device.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of International Application No.PCT/KR2021/013307, filed on Sep. 29, 2021, which claims the benefit ofearlier filing date and right of priority to Korean Patent ApplicationNos. 10-2020-0127034, filed on Sep. 29, 2020, 10-2020-0130526, filed onOct. 8, 2020, 10-2020-0136766, filed on Oct. 21, 2020, 10-2020-0183032,filed on Dec. 24, 2020, 10-2021-0002126, filed on Jan. 7, 2021,10-2021-0060177, filed on May 10, 2021, and 10-2021-0106887, filed onAug. 12, 2021, and also claims the benefit of U.S. ProvisionalApplication No. 63/138,778, filed on Jan. 18, 2021, the contents ofwhich are all hereby incorporated by reference herein in their entirety.

TECHNICAL FIELD

This disclosure relates to a wireless communication system.

BACKGROUND

Sidelink (SL) communication is a communication scheme in which a directlink is established between User Equipments (UEs) and the UEs exchangevoice and data directly with each other without intervention of anevolved Node B (eNB). SL communication is under consideration as asolution to the overhead of an eNB caused by rapidly increasing datatraffic. Vehicle-to-everything (V2X) refers to a communicationtechnology through which a vehicle exchanges information with anothervehicle, a pedestrian, an object having an infrastructure (or infra)established therein, and so on. The V2X may be divided into 4 types,such as vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I),vehicle-to-network (V2N), and vehicle-to-pedestrian (V2P). The V2Xcommunication may be provided via a PC5 interface and/or Uu interface.

Meanwhile, as a wider range of communication devices require largercommunication capacities, the need for mobile broadband communicationthat is more enhanced than the existing Radio Access Technology (RAT) isrising. Accordingly, discussions are made on services and user equipment(UE) that are sensitive to reliability and latency. And, a nextgeneration radio access technology that is based on the enhanced mobilebroadband communication, massive Machine Type Communication (MTC),Ultra-Reliable and Low Latency Communication (URLLC), and so on, may bereferred to as a new radio access technology (RAT) or new radio (NR).Herein, the NR may also support vehicle-to-everything (V2X)communication.

FIG. 1 is a drawing for describing V2X communication based on NR,compared to V2X communication based on RAT used before NR. Theembodiment of FIG. 1 may be combined with various embodiments of thepresent disclosure.

Regarding V2X communication, a scheme of providing a safety service,based on a V2X message such as Basic Safety Message (BSM), CooperativeAwareness Message (CAM), and Decentralized Environmental NotificationMessage (DENM) is focused in the discussion on the RAT used before theNR. The V2X message may include position information, dynamicinformation, attribute information, or the like. For example, a UE maytransmit a periodic message type CAM and/or an event triggered messagetype DENM to another UE.

Thereafter, regarding V2X communication, various V2X scenarios areproposed in NR. For example, the various V2X scenarios may includevehicle platooning, advanced driving, extended sensors, remote driving,or the like.

SUMMARY

Meanwhile, a first device may receive an assistance information requestfrom a second device, and the first device may transmit assistanceinformation to the second device in response to the assistanceinformation request. In addition, the second device may select SLresource(s) based on the assistance information. In this case, the formof the assistance information, conditions for using the assistanceinformation, conditions for transmitting the assistance information,etc. need to be specifically defined. Furthermore, information includedin the assistance information request needs to be specifically defined.

In one embodiment, provided is a method for performing wirelesscommunication by a first device. The method may comprise: receiving,from a second device, an assistance information request; generatingassistance information based on the assistance information request;transmitting, to the second device through a physical sidelink controlchannel (PSCCH), first sidelink control information (SCI) includingscheduling information for a physical sidelink shared channel (PSSCH),wherein the first SCI includes information related to frequency resourceassignment, information related to time resource assignment, informationrelated to a demodulation reference signal (DMRS) pattern, andinformation related to modulation and coding scheme (MCS); andtransmitting, to the second device through the PSSCH, the assistanceinformation in response to the assistance information request, whereinthe assistance information includes information for sidelink (SL)resource selection of the second device.

In one embodiment, provided is a first device adapted to performwireless communication. The first device may comprise: one or morememories storing instructions; one or more transceivers; and one or moreprocessors connected to the one or more memories and the one or moretransceivers. For example, the one or more processors may execute theinstructions to: receive, from a second device, an assistanceinformation request; generate assistance information based on theassistance information request; transmit, to the second device through aphysical sidelink control channel (PSCCH), first sidelink controlinformation (SCI) including scheduling information for a physicalsidelink shared channel (PSSCH), wherein the first SCI includesinformation related to frequency resource assignment, informationrelated to time resource assignment, information related to ademodulation reference signal (DMRS) pattern, and information related tomodulation and coding scheme (MCS); and transmit, to the second devicethrough the PSSCH, the assistance information in response to theassistance information request, wherein the assistance informationincludes information for sidelink (SL) resource selection of the seconddevice.

The user equipment (UE) can efficiently perform SL communication.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a drawing for describing V2X communication based on NR,compared to V2X communication based on RAT used before NR.

FIG. 2 shows a structure of an NR system, based on an embodiment of thepresent disclosure.

FIG. 3 shows a radio protocol architecture, based on an embodiment ofthe present disclosure.

FIG. 4 shows a structure of a radio frame of an NR, based on anembodiment of the present disclosure.

FIG. 5 shows a structure of a slot of an NR frame, based on anembodiment of the present disclosure.

FIG. 6 shows an example of a BWP, based on an embodiment of the presentdisclosure.

FIG. 7 shows a UE performing V2X or SL communication, based on anembodiment of the present disclosure.

FIG. 8 shows a procedure of performing V2X or SL communication by a UEbased on a transmission mode, based on an embodiment of the presentdisclosure.

FIG. 9 shows three cast types, based on an embodiment of the presentdisclosure.

FIG. 10 shows a resource unit for CBR measurement, based on anembodiment of the present disclosure.

FIG. 11 shows a procedure for a UE-A to transmit assistance informationto a UE-B, based on an embodiment of the present disclosure.

FIG. 12 shows a procedure for the UE-A to transmit assistanceinformation to the UE-B, based on an embodiment of the presentdisclosure.

FIG. 13 shows a procedure for a UE to perform SL communication based onassistance information, based on an embodiment of the presentdisclosure.

FIG. 14 shows a procedure for a UE to perform SL communication based onassistance information, based on an embodiment of the presentdisclosure.

FIG. 15 shows a method for performing wireless communication by a firstdevice, based on an embodiment of the present disclosure.

FIG. 16 shows a method for performing wireless communication by a seconddevice, based on an embodiment of the present disclosure.

FIG. 17 shows a communication system 1, based on an embodiment of thepresent disclosure.

FIG. 18 shows wireless devices, based on an embodiment of the presentdisclosure.

FIG. 19 shows a signal process circuit for a transmission signal, basedon an embodiment of the present disclosure.

FIG. 20 shows another example of a wireless device, based on anembodiment of the present disclosure.

FIG. 21 shows a hand-held device, based on an embodiment of the presentdisclosure.

FIG. 22 shows a vehicle or an autonomous vehicle, based on an embodimentof the present disclosure.

DETAILED DESCRIPTION

In the present specification, “A or B” may mean “only A”, “only B” or“both A and B.” In other words, in the present specification, “A or B”may be interpreted as “A and/or B”. For example, in the presentspecification, “A, B, or C” may mean “only A”, “only B”, “only C”, or“any combination of A, B, C”.

A slash (/) or comma used in the present specification may mean“and/or”. For example, “A/B” may mean “A and/or B”. Accordingly, “A/B”may mean “only A”, “only B”, or “both A and B”. For example, “A, B, C”may mean “A, B, or C”.

In the present specification, “at least one of A and B” may mean “onlyA”, “only B”, or “both A and B”. In addition, in the presentspecification, the expression “at least one of A or B” or “at least oneof A and/or B” may be interpreted as “at least one of A and B”.

In addition, in the present specification, “at least one of A, B, and C”may mean “only A”, “only B”, “only C”, or “any combination of A, B, andC”. In addition, “at least one of A, B, or C” or “at least one of A, B,and/or C” may mean “at least one of A, B, and C”.

In addition, a parenthesis used in the present specification may mean“for example”. Specifically, when indicated as “control information(PDCCH)”, it may mean that “PDCCH” is proposed as an example of the“control information”. In other words, the “control information” of thepresent specification is not limited to “PDCCH”, and “PDCCH” may beproposed as an example of the “control information”. In addition, whenindicated as “control information (i.e., PDCCH)”, it may also mean that“PDCCH” is proposed as an example of the “control information”.

A technical feature described individually in one figure in the presentspecification may be individually implemented, or may be simultaneouslyimplemented.

The technology described below may be used in various wirelesscommunication systems such as code division multiple access (CDMA),frequency division multiple access (FDMA), time division multiple access(TDMA), orthogonal frequency division multiple access (OFDMA), singlecarrier frequency division multiple access (SC-FDMA), and so on. TheCDMA may be implemented with a radio technology, such as universalterrestrial radio access (UTRA) or CDMA-2000. The TDMA may beimplemented with a radio technology, such as global system for mobilecommunications (GSM)/general packet ratio service (GPRS)/enhanced datarate for GSM evolution (EDGE). The OFDMA may be implemented with a radiotechnology, such as institute of electrical and electronics engineers(IEEE) 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, evolved UTRA(E-UTRA), and so on. IEEE 802.16m is an evolved version of IEEE 802.16eand provides backward compatibility with a system based on the IEEE802.16e. The UTRA is part of a universal mobile telecommunication system(UMTS). 3rd generation partnership project (3GPP) long term evolution(LTE) is part of an evolved UMTS (E-UMTS) using the E-UTRA. The 3GPP LTEuses the OFDMA in a downlink and uses the SC-FDMA in an uplink.LTE-advanced (LTE-A) is an evolution of the LTE.

5G NR is a successive technology of LTE-A corresponding to a newClean-slate type mobile communication system having the characteristicsof high performance, low latency, high availability, and so on. 5G NRmay use resources of all spectrum available for usage including lowfrequency bands of less than 1 GHz, middle frequency bands ranging from1 GHz to 10 GHz, high frequency (millimeter waves) of 24 GHz or more,and so on.

For clarity in the description, the following description will mostlyfocus on LTE-A or 5G NR. However, technical features according to anembodiment of the present disclosure will not be limited only to this.

FIG. 2 shows a structure of an NR system, based on an embodiment of thepresent disclosure. The embodiment of FIG. 2 may be combined withvarious embodiments of the present disclosure.

Referring to FIG. 2 , a next generation-radio access network (NG-RAN)may include a BS 20 providing a UE 10 with a user plane and controlplane protocol termination. For example, the BS 20 may include a nextgeneration-Node B (gNB) and/or an evolved-NodeB (eNB). For example, theUE 10 may be fixed or mobile and may be referred to as other terms, suchas a mobile station (MS), a user terminal (UT), a subscriber station(SS), a mobile terminal (MT), wireless device, and so on. For example,the BS may be referred to as a fixed station which communicates with theUE 10 and may be referred to as other terms, such as a base transceiversystem (BTS), an access point (AP), and so on.

The embodiment of FIG. 2 exemplifies a case where only the gNB isincluded. The BSs 20 may be connected to one another via Xn interface.The BS 20 may be connected to one another via 5th generation (5G) corenetwork (5GC) and NG interface. More specifically, the BSs 20 may beconnected to an access and mobility management function (AMF) 30 viaNG-C interface, and may be connected to a user plane function (UPF) 30via NG-U interface.

Layers of a radio interface protocol between the UE and the network canbe classified into a first layer (layer 1, L1), a second layer (layer 2,L2), and a third layer (layer 3, L3) based on the lower three layers ofthe open system interconnection (OSI) model that is well-known in thecommunication system. Among them, a physical (PHY) layer belonging tothe first layer provides an information transfer service by using aphysical channel, and a radio resource control (RRC) layer belonging tothe third layer serves to control a radio resource between the UE andthe network. For this, the RRC layer exchanges an RRC message betweenthe UE and the BS.

FIG. 3 shows a radio protocol architecture, based on an embodiment ofthe present disclosure. The embodiment of FIG. 3 may be combined withvarious embodiments of the present disclosure. Specifically, (a) of FIG.3 shows a radio protocol stack of a user plane for Uu communication, and(b) of FIG. 3 shows a radio protocol stack of a control plane for Uucommunication. (c) of FIG. 3 shows a radio protocol stack of a userplane for SL communication, and (d) of FIG. 3 shows a radio protocolstack of a control plane for SL communication.

Referring to FIG. 3 , a physical layer provides an upper layer with aninformation transfer service through a physical channel. The physicallayer is connected to a medium access control (MAC) layer which is anupper layer of the physical layer through a transport channel. Data istransferred between the MAC layer and the physical layer through thetransport channel. The transport channel is classified according to howand with what characteristics data is transmitted through a radiointerface.

Between different physical layers, i.e., a physical layer of atransmitter and a physical layer of a receiver, data are transferredthrough the physical channel. The physical channel is modulated using anorthogonal frequency division multiplexing (OFDM) scheme, and utilizestime and frequency as a radio resource.

The MAC layer provides services to a radio link control (RLC) layer,which is a higher layer of the MAC layer, via a logical channel. The MAClayer provides a function of mapping multiple logical channels tomultiple transport channels. The MAC layer also provides a function oflogical channel multiplexing by mapping multiple logical channels to asingle transport channel. The MAC layer provides data transfer servicesover logical channels.

The RLC layer performs concatenation, segmentation, and reassembly ofRadio Link Control Service Data Unit (RLC SDU). In order to ensurediverse quality of service (QoS) required by a radio bearer (RB), theRLC layer provides three types of operation modes, i.e., a transparentmode (TM), an unacknowledged mode (UM), and an acknowledged mode (AM).An AM RLC provides error correction through an automatic repeat request(ARQ).

A radio resource control (RRC) layer is defined only in the controlplane. The RRC layer serves to control the logical channel, thetransport channel, and the physical channel in association withconfiguration, reconfiguration and release of RBs. The RB is a logicalpath provided by the first layer (i.e., the physical layer or the PHYlayer) and the second layer (i.e., a MAC layer, an RLC layer, a packetdata convergence protocol (PDCP) layer, and a service data adaptationprotocol (SDAP) layer) for data delivery between the UE and the network.

Functions of a packet data convergence protocol (PDCP) layer in the userplane include user data delivery, header compression, and ciphering.Functions of a PDCP layer in the control plane include control-planedata delivery and ciphering/integrity protection.

A service data adaptation protocol (SDAP) layer is defined only in auser plane. The SDAP layer performs mapping between a Quality of Service(QoS) flow and a data radio bearer (DRB) and QoS flow ID (QFI) markingin both DL and UL packets.

The configuration of the RB implies a process for specifying a radioprotocol layer and channel properties to provide a particular serviceand for determining respective detailed parameters and operations. TheRB can be classified into two types, i.e., a signaling RB (SRB) and adata RB (DRB). The SRB is used as a path for transmitting an RRC messagein the control plane. The DRB is used as a path for transmitting userdata in the user plane.

When an RRC connection is established between an RRC layer of the UE andan RRC layer of the E-UTRAN, the UE is in an RRC_CONNECTED state, and,otherwise, the UE may be in an RRC_IDLE state. In case of the NR, anRRC_INACTIVE state is additionally defined, and a UE being in theRRC_INACTIVE state may maintain its connection with a core networkwhereas its connection with the BS is released.

Data is transmitted from the network to the UE through a downlinktransport channel. Examples of the downlink transport channel include abroadcast channel (BCH) for transmitting system information and adownlink-shared channel (SCH) for transmitting user traffic or controlmessages. Traffic of downlink multicast or broadcast services or thecontrol messages can be transmitted on the downlink-SCH or an additionaldownlink multicast channel (MCH). Data is transmitted from the UE to thenetwork through an uplink transport channel. Examples of the uplinktransport channel include a random access channel (RACH) fortransmitting an initial control message and an uplink SCH fortransmitting user traffic or control messages.

Examples of logical channels belonging to a higher channel of thetransport channel and mapped onto the transport channels include abroadcast channel (BCCH), a paging control channel (PCCH), a commoncontrol channel (CCCH), a multicast control channel (MCCH), a multicasttraffic channel (MTCH), etc.

FIG. 4 shows a structure of a radio frame of an NR, based on anembodiment of the present disclosure. The embodiment of FIG. 4 may becombined with various embodiments of the present disclosure.

Referring to FIG. 4 , in the NR, a radio frame may be used forperforming uplink and downlink transmission. A radio frame has a lengthof 10 ms and may be defined to be configured of two half-frames (HFs). Ahalf-frame may include five 1 ms subframes (SFs). A subframe (SF) may bedivided into one or more slots, and the number of slots within asubframe may be determined based on subcarrier spacing (SCS). Each slotmay include 12 or 14 OFDM(A) symbols according to a cyclic prefix (CP).

In case of using a normal CP, each slot may include 14 symbols. In caseof using an extended CP, each slot may include 12 symbols. Herein, asymbol may include an OFDM symbol (or CP-OFDM symbol) and a SingleCarrier-FDMA (SC-FDMA) symbol (or Discrete Fourier Transform-spread-OFDM(DFT-s-OFDM) symbol).

Table 1 shown below represents an example of a number of symbols perslot (N^(slot) _(symb)), a number slots per frame (N^(frame,u) _(slot)),and a number of slots per subframe (N^(subframe,u) _(slot)) based on anSCS configuration (u), in a case where a normal CP is used.

TABLE 1 SCS (15 * 2^(u)) N^(slot) _(symb) N^(frame,u) _(slot)N^(subframe,u) _(slot) 15 KHz (u = 0) 14 10 1 30 KHz (u = 1) 14 20 2 60KHz (u = 2) 14 40 4 120 KHz (u = 3)  14 80 8 240 KHz (u = 4)  14 160 16

Table 2 shows an example of a number of symbols per slot, a number ofslots per frame, and a number of slots per subframe based on the SCS, ina case where an extended CP is used.

TABLE 2 SCS (15 * 2^(u)) N^(slot) _(symb) N^(frame,u) _(slot)N^(subframe,u) _(slot) 60 KHz (u = 2) 12 40 4

In an NR system, OFDM(A) numerologies (e.g., SCS, CP length, and so on)between multiple cells being integrate to one UE may be differentlyconfigured. Accordingly, a (absolute time) duration (or section) of atime resource (e.g., subframe, slot or TTI) (collectively referred to asa time unit (TU) for simplicity) being configured of the same number ofsymbols may be differently configured in the integrated cells.

In the NR, multiple numerologies or SCSs for supporting diverse 5Gservices may be supported. For example, in case an SCS is 15 kHz, a widearea of the conventional cellular bands may be supported, and, in casean SCS is 30 kHz/60 kHz a dense-urban, lower latency, wider carrierbandwidth may be supported. In case the SCS is 60 kHz or higher, abandwidth that is greater than 24.25 GHz may be used in order toovercome phase noise.

An NR frequency band may be defined as two different types of frequencyranges. The two different types of frequency ranges may be FR1 and FR2.The values of the frequency ranges may be changed (or varied), and, forexample, the two different types of frequency ranges may be as shownbelow in Table 3. Among the frequency ranges that are used in an NRsystem, FR1 may mean a “sub 6 GHz range”, and FR2 may mean an “above 6GHz range” and may also be referred to as a millimeter wave (mmW).

TABLE 3 Frequency Range Corresponding frequency Subcarrier designationrange Spacing (SCS) FR1  450 MHz-6000 MHz  15, 30, 60 kHz FR2 24250MHz-52600 MHz 60, 120, 240 kHz

As described above, the values of the frequency ranges in the NR systemmay be changed (or varied). For example, as shown below in Table 4, FR1may include a band within a range of 410 MHz to 7125 MHz. Morespecifically, FR1 may include a frequency band of 6 GHz (or 5850, 5900,5925 MHz, and so on) and higher. For example, a frequency band of 6 GHz(or 5850, 5900, 5925 MHz, and so on) and higher being included in FR1mat include an unlicensed band. The unlicensed band may be used fordiverse purposes, e.g., the unlicensed band for vehicle-specificcommunication (e.g., automated driving).

TABLE 4 Frequency Range Corresponding frequency Subcarrier designationrange Spacing (SCS) FR1  410 MHz-7125 MHz  15, 30, 60 kHz FR2 24250MHz-52600 MHz 60, 120, 240 kHz

FIG. 5 shows a structure of a slot of an NR frame, based on anembodiment of the present disclosure. The embodiment of FIG. 5 may becombined with various embodiments of the present disclosure.

Referring to FIG. 5 , a slot includes a plurality of symbols in a timedomain. For example, in case of a normal CP, one slot may include 14symbols. However, in case of an extended CP, one slot may include 12symbols. Alternatively, in case of a normal CP, one slot may include 7symbols. However, in case of an extended CP, one slot may include 6symbols.

A carrier includes a plurality of subcarriers in a frequency domain. AResource Block (RB) may be defined as a plurality of consecutivesubcarriers (e.g., 12 subcarriers) in the frequency domain. A BandwidthPart (BWP) may be defined as a plurality of consecutive (Physical)Resource Blocks ((P)RBs) in the frequency domain, and the BWP maycorrespond to one numerology (e.g., SCS, CP length, and so on). Acarrier may include a maximum of N number BWPs (e.g., 5 BWPs). Datacommunication may be performed via an activated BWP. Each element may bereferred to as a Resource Element (RE) within a resource grid and onecomplex symbol may be mapped to each element.

Hereinafter, a bandwidth part (BWP) and a carrier will be described.

The BWP may be a set of consecutive physical resource blocks (PRBs) in agiven numerology. The PRB may be selected from consecutive sub-sets ofcommon resource blocks (CRBs) for the given numerology on a givencarrier

For example, the BWP may be at least any one of an active BWP, aninitial BWP, and/or a default BWP. For example, the UE may not monitordownlink radio link quality in a DL BWP other than an active DL BWP on aprimary cell (PCell). For example, the UE may not receive PDCCH,physical downlink shared channel (PDSCH), or channel stateinformation-reference signal (CSI-RS) (excluding RRM) outside the activeDL BWP. For example, the UE may not trigger a channel state information(CSI) report for the inactive DL BWP. For example, the UE may nottransmit physical uplink control channel (PUCCH) or physical uplinkshared channel (PUSCH) outside an active UL BWP. For example, in adownlink case, the initial BWP may be given as a consecutive RB set fora remaining minimum system information (RMSI) control resource set(CORESET) (configured by physical broadcast channel (PBCH)). Forexample, in an uplink case, the initial BWP may be given by systeminformation block (SIB) for a random access procedure. For example, thedefault BWP may be configured by a higher layer. For example, an initialvalue of the default BWP may be an initial DL BWP. For energy saving, ifthe UE fails to detect downlink control information (DCI) during aspecific period, the UE may switch the active BWP of the UE to thedefault BWP.

Meanwhile, the BWP may be defined for SL. The same SL BWP may be used intransmission and reception. For example, a transmitting UE may transmitan SL channel or an SL signal on a specific BWP, and a receiving UE mayreceive the SL channel or the SL signal on the specific BWP. In alicensed carrier, the SL BWP may be defined separately from a Uu BWP,and the SL BWP may have configuration signaling separate from the UuBWP. For example, the UE may receive a configuration for the SL BWP fromthe BS/network. For example, the UE may receive a configuration for theUu BWP from the BS/network. The SL BWP may be (pre-)configured in acarrier with respect to an out-of-coverage NR V2X UE and an RRC_IDLE UE.For the UE in the RRC_CONNECTED mode, at least one SL BWP may beactivated in the carrier.

FIG. 6 shows an example of a BWP, based on an embodiment of the presentdisclosure. The embodiment of FIG. 6 may be combined with variousembodiments of the present disclosure. It is assumed in the embodimentof FIG. 6 that the number of BWPs is 3.

Referring to FIG. 6 , a common resource block (CRB) may be a carrierresource block numbered from one end of a carrier band to the other endthereof. In addition, the PRB may be a resource block numbered withineach BWP. A point A may indicate a common reference point for a resourceblock grid.

The BWP may be configured by a point A, an offset N^(start) _(BWP) fromthe point A, and a bandwidth N^(size) _(BWP). For example, the point Amay be an external reference point of a PRB of a carrier in which asubcarrier 0 of all numerologies (e.g., all numerologies supported by anetwork on that carrier) is aligned. For example, the offset may be aPRB interval between a lowest subcarrier and the point A in a givennumerology. For example, the bandwidth may be the number of PRBs in thegiven numerology.

Hereinafter, V2X or SL communication will be described.

A sidelink synchronization signal (SLSS) may include a primary sidelinksynchronization signal (PSSS) and a secondary sidelink synchronizationsignal (SSSS), as an SL-specific sequence. The PSSS may be referred toas a sidelink primary synchronization signal (S-PSS), and the SSSS maybe referred to as a sidelink secondary synchronization signal (S-SSS).For example, length-127 M-sequences may be used for the S-PSS, andlength-127 gold sequences may be used for the S-SSS. For example, a UEmay use the S-PSS for initial signal detection and for synchronizationacquisition. For example, the UE may use the S-PSS and the S-SSS foracquisition of detailed synchronization and for detection of asynchronization signal ID.

A physical sidelink broadcast channel (PSBCH) may be a (broadcast)channel for transmitting default (system) information which must befirst known by the UE before SL signal transmission/reception. Forexample, the default information may be information related to SLSS, aduplex mode (DM), a time division duplex (TDD) uplink/downlink (UL/DL)configuration, information related to a resource pool, a type of anapplication related to the SLSS, a subframe offset, broadcastinformation, or the like. For example, for evaluation of PSBCHperformance, in NR V2X, a payload size of the PSBCH may be 56 bitsincluding 24-bit cyclic redundancy check (CRC).

The S-PSS, the S-SSS, and the PSBCH may be included in a block format(e.g., SL synchronization signal (SS)/PSBCH block, hereinafter,sidelink-synchronization signal block (S-SSB)) supporting periodicaltransmission. The S-SSB may have the same numerology (i.e., SCS and CPlength) as a physical sidelink control channel (PSCCH)/physical sidelinkshared channel (PSSCH) in a carrier, and a transmission bandwidth mayexist within a (pre-)configured sidelink (SL) BWP. For example, theS-SSB may have a bandwidth of 11 resource blocks (RBs). For example, thePSBCH may exist across 11 RBs. In addition, a frequency position of theS-SSB may be (pre-)configured. Accordingly, the UE does not have toperform hypothesis detection at frequency to discover the S-SSB in thecarrier.

FIG. 7 shows a UE performing V2X or SL communication, based on anembodiment of the present disclosure. The embodiment of FIG. 7 may becombined with various embodiments of the present disclosure.

Referring to FIG. 7 , in V2X or SL communication, the term ‘UE’ maygenerally imply a UE of a user. However, if a network equipment such asa BS transmits/receives a signal according to a communication schemebetween UEs, the BS may also be regarded as a sort of the UE. Forexample, a UE 1 may be a first apparatus 100, and a UE 2 may be a secondapparatus 200.

For example, the UE 1 may select a resource unit corresponding to aspecific resource in a resource pool which implies a set of series ofresources. In addition, the UE 1 may transmit an SL signal by using theresource unit. For example, a resource pool in which the UE 1 is capableof transmitting a signal may be configured to the UE 2 which is areceiving UE, and the signal of the UE 1 may be detected in the resourcepool.

Herein, if the UE 1 is within a connectivity range of the BS, the BS mayinform the UE 1 of the resource pool. Otherwise, if the UE 1 is out ofthe connectivity range of the BS, another UE may inform the UE 1 of theresource pool, or the UE 1 may use a pre-configured resource pool.

In general, the resource pool may be configured in unit of a pluralityof resources, and each UE may select a unit of one or a plurality ofresources to use it in SL signal transmission thereof.

Hereinafter, resource allocation in SL will be described.

FIG. 8 shows a procedure of performing V2X or SL communication by a UEbased on a transmission mode, based on an embodiment of the presentdisclosure. The embodiment of FIG. 8 may be combined with variousembodiments of the present disclosure. In various embodiments of thepresent disclosure, the transmission mode may be called a mode or aresource allocation mode. Hereinafter, for convenience of explanation,in LTE, the transmission mode may be called an LTE transmission mode. InNR, the transmission mode may be called an NR resource allocation mode.

For example, (a) of FIG. 8 shows a UE operation related to an LTEtransmission mode 1 or an LTE transmission mode 3. Alternatively, forexample, (a) of FIG. 8 shows a UE operation related to an NR resourceallocation mode 1. For example, the LTE transmission mode 1 may beapplied to general SL communication, and the LTE transmission mode 3 maybe applied to V2X communication.

For example, (b) of FIG. 8 shows a UE operation related to an LTEtransmission mode 2 or an LTE transmission mode 4. Alternatively, forexample, (b) of FIG. 8 shows a UE operation related to an NR resourceallocation mode 2.

Referring to (a) of FIG. 8 , in the LTE transmission mode 1, the LTEtransmission mode 3, or the NR resource allocation mode 1, a BS mayschedule an SL resource to be used by the UE for SL transmission. Forexample, the BS may perform resource scheduling to a UE 1 through aPDCCH (e.g., downlink control information (DCI)) or RRC signaling (e.g.,Configured Grant Type 1 or Configured Grant Type 2), and the UE 1 mayperform V2X or SL communication with respect to a UE 2 according to theresource scheduling. For example, the UE 1 may transmit sidelink controlinformation (SCI) to the UE 2 through a physical sidelink controlchannel (PSCCH), and thereafter transmit data based on the SCI to the UE2 through a physical sidelink shared channel (PSSCH).

Referring to (b) of FIG. 8 , in the LTE transmission mode 2, the LTEtransmission mode 4, or the NR resource allocation mode 2, the UE maydetermine an SL transmission resource within an SL resource configuredby a BS/network or a pre-configured SL resource. For example, theconfigured SL resource or the pre-configured SL resource may be aresource pool. For example, the UE may autonomously select or schedule aresource for SL transmission. For example, the UE may perform SLcommunication by autonomously selecting a resource within a configuredresource pool. For example, the UE may autonomously select a resourcewithin a selective window by performing a sensing and resource(re)selection procedure. For example, the sensing may be performed inunit of subchannels. In addition, the UE 1 which has autonomouslyselected the resource within the resource pool may transmit the SCI tothe UE 2 through a PSCCH, and thereafter may transmit data based on theSCI to the UE 2 through a PSSCH.

FIG. 9 shows three cast types, based on an embodiment of the presentdisclosure. The embodiment of FIG. 9 may be combined with variousembodiments of the present disclosure. Specifically, (a) of FIG. 9 showsbroadcast-type SL communication, (b) of FIG. 9 shows unicast type-SLcommunication, and (c) of FIG. 9 shows groupcast-type SL communication.In case of the unicast-type SL communication, a UE may performone-to-one communication with respect to another UE. In case of thegroupcast-type SL transmission, the UE may perform SL communication withrespect to one or more UEs in a group to which the UE belongs. Invarious embodiments of the present disclosure, SL groupcastcommunication may be replaced with SL multicast communication, SLone-to-many communication, or the like.

Hereinafter, sidelink (SL) congestion control will be described.

If a UE autonomously determines an SL transmission resource, the UE alsoautonomously determines a size and frequency of use for a resource usedby the UE. Of course, due to a constraint from a network or the like, itmay be restricted to use a resource size or frequency of use, which isgreater than or equal to a specific level. However, if all UEs use arelatively great amount of resources in a situation where many UEs areconcentrated in a specific region at a specific time, overallperformance may significantly deteriorate due to mutual interference.

Accordingly, the UE may need to observe a channel situation. If it isdetermined that an excessively great amount of resources are consumed,it is preferable that the UE autonomously decreases the use ofresources. In the present disclosure, this may be defined as congestioncontrol (CR). For example, the UE may determine whether energy measuredin a unit time/frequency resource is greater than or equal to a specificlevel, and may adjust an amount and frequency of use for itstransmission resource based on a ratio of the unit time/frequencyresource in which the energy greater than or equal to the specific levelis observed. In the present disclosure, the ratio of the time/frequencyresource in which the energy greater than or equal to the specific levelis observed may be defined as a channel busy ratio (CBR). The UE maymeasure the CBR for a channel/frequency. Additionally, the UE maytransmit the measured CBR to the network/BS.

FIG. 10 shows a resource unit for CBR measurement, based on anembodiment of the present disclosure. The embodiment of FIG. 10 may becombined with various embodiments of the present disclosure.

Referring to FIG. 10 , CBR may denote the number of sub-channels inwhich a measurement result value of a received signal strength indicator(RSSI) has a value greater than or equal to a pre-configured thresholdas a result of measuring the RSSI by a UE on a sub-channel basis for aspecific period (e.g., 100 ms). Alternatively, the CBR may denote aratio of sub-channels having a value greater than or equal to apre-configured threshold among sub-channels for a specific duration. Forexample, in the embodiment of FIG. 10 , if it is assumed that a hatchedsub-channel is a sub-channel having a value greater than or equal to apre-configured threshold, the CBR may denote a ratio of the hatchedsub-channels for a period of 100 ms. Additionally, the UE may report theCBR to the BS.

Further, congestion control considering a priority of traffic (e.g.packet) may be necessary. To this end, for example, the UE may measure achannel occupancy ratio (CR). Specifically, the UE may measure the CBR,and the UE may determine a maximum value CRlimitk of a channel occupancyratio k (CRk) that can be occupied by traffic corresponding to eachpriority (e.g., k) based on the CBR. For example, the UE may derive themaximum value CRlimitk of the channel occupancy ratio with respect to apriority of each traffic, based on a predetermined table of CBRmeasurement values. For example, in case of traffic having a relativelyhigh priority, the UE may derive a maximum value of a relatively greatchannel occupancy ratio. Thereafter, the UE may perform congestioncontrol by restricting a total sum of channel occupancy ratios oftraffic, of which a priority k is lower than i, to a value less than orequal to a specific value. Based on this method, the channel occupancyratio may be more strictly restricted for traffic having a relativelylow priority.

In addition thereto, the UE may perform SL congestion control by using amethod of adjusting a level of transmit power, dropping a packet,determining whether retransmission is to be performed, adjusting atransmission RB size (Modulation and Coding Scheme (MCS) coordination),or the like.

Hereinafter, a hybrid automatic repeat request (HARQ) procedure will bedescribed.

In case of SL unicast and groupcast, HARQ feedback and HARQ combining inthe physical layer may be supported. For example, when a receiving UEoperates in a resource allocation mode 1 or 2, the receiving UE mayreceive the PSSCH from a transmitting UE, and the receiving UE maytransmit HARQ feedback for the PSSCH to the transmitting UE by using asidelink feedback control information (SFCI) format through a physicalsidelink feedback channel (PSFCH).

For example, the SL HARQ feedback may be enabled for unicast. In thiscase, in a non-code block group (non-CBG) operation, if the receiving UEdecodes a PSCCH of which a target is the receiving UE and if thereceiving UE successfully decodes a transport block related to thePSCCH, the receiving UE may generate HARQ-ACK. In addition, thereceiving UE may transmit the HARQ-ACK to the transmitting UE.Otherwise, if the receiving UE cannot successfully decode the transportblock after decoding the PSCCH of which the target is the receiving UE,the receiving UE may generate the HARQ-NACK. In addition, the receivingUE may transmit HARQ-NACK to the transmitting UE.

For example, the SL HARQ feedback may be enabled for groupcast. Forexample, in the non-CBG operation, two HARQ feedback options may besupported for groupcast.

(1) Groupcast option 1: After the receiving UE decodes the PSCCH ofwhich the target is the receiving UE, if the receiving UE fails indecoding of a transport block related to the PSCCH, the receiving UE maytransmit HARQ-NACK to the transmitting UE through a PSFCH. Otherwise, ifthe receiving UE decodes the PSCCH of which the target is the receivingUE and if the receiving UE successfully decodes the transport blockrelated to the PSCCH, the receiving UE may not transmit the HARQ-ACK tothe transmitting UE.

(2) Groupcast option 2: After the receiving UE decodes the PSCCH ofwhich the target is the receiving UE, if the receiving UE fails indecoding of the transport block related to the PSCCH, the receiving UEmay transmit HARQ-NACK to the transmitting UE through the PSFCH. Inaddition, if the receiving UE decodes the PSCCH of which the target isthe receiving UE and if the receiving UE successfully decodes thetransport block related to the PSCCH, the receiving UE may transmit theHARQ-ACK to the transmitting UE through the PSFCH.

For example, if the groupcast option 1 is used in the SL HARQ feedback,all UEs performing groupcast communication may share a PSFCH resource.For example, UEs belonging to the same group may transmit HARQ feedbackby using the same PSFCH resource.

For example, if the groupcast option 2 is used in the SL HARQ feedback,each UE performing groupcast communication may use a different PSFCHresource for HARQ feedback transmission. For example, UEs belonging tothe same group may transmit HARQ feedback by using different PSFCHresources.

For example, when the SL HARQ feedback is enabled for groupcast, thereceiving UE may determine whether to transmit the HARQ feedback to thetransmitting UE based on a transmission-reception (TX-RX) distanceand/or reference signal received power (RSRP).

For example, in the groupcast option 1, in case of the TX-RXdistance-based HARQ feedback, if the TX-RX distance is less than orequal to a communication range requirement, the receiving UE maytransmit HARQ feedback for the PSSCH to the transmitting UE. Otherwise,if the TX-RX distance is greater than the communication rangerequirement, the receiving UE may not transmit the HARQ feedback for thePSSCH to the transmitting UE. For example, the transmitting UE mayinform the receiving UE of a location of the transmitting UE through SCIrelated to the PSSCH. For example, the SCI related to the PSSCH may besecond SCI. For example, the receiving UE may estimate or obtain theTX-RX distance based on a location of the receiving UE and the locationof the transmitting UE. For example, the receiving UE may decode the SCIrelated to the PSSCH and thus may know the communication rangerequirement used in the PSSCH.

For example, in case of the resource allocation mode 1, a time (offset)between the PSFCH and the PSSCH may be configured or pre-configured. Incase of unicast and groupcast, if retransmission is necessary on SL,this may be indicated to a BS by an in-coverage UE which uses the PUCCH.The transmitting UE may transmit an indication to a serving BS of thetransmitting UE in a form of scheduling request (SR)/buffer statusreport (BSR), not a form of HARQ ACK/NACK. In addition, even if the BSdoes not receive the indication, the BS may schedule an SLretransmission resource to the UE. For example, in case of the resourceallocation mode 2, a time (offset) between the PSFCH and the PSSCH maybe configured or pre-configured.

For example, from a perspective of UE transmission in a carrier, TDMbetween the PSCCH/PSSCH and the PSFCH may be allowed for a PSFCH formatfor SL in a slot. For example, a sequence-based PSFCH format having asingle symbol may be supported. Herein, the single symbol may not an AGCduration. For example, the sequence-based PSFCH format may be applied tounicast and groupcast.

For example, in a slot related to a resource pool, a PSFCH resource maybe configured periodically as N slot durations, or may bepre-configured. For example, N may be configured as one or more valuesgreater than or equal to 1. For example, N may be 1, 2, or 4. Forexample, HARQ feedback for transmission in a specific resource pool maybe transmitted only through a PSFCH on the specific resource pool.

For example, if the transmitting UE transmits the PSSCH to the receivingUE across a slot #X to a slot #N, the receiving UE may transmit HARQfeedback for the PSSCH to the transmitting UE in a slot #(N+A). Forexample, the slot #(N+A) may include a PSFCH resource. Herein, forexample, A may be a smallest integer greater than or equal to K. Forexample, K may be the number of logical slots. In this case, K may bethe number of slots in a resource pool. Alternatively, for example, Kmay be the number of physical slots. In this case, K may be the numberof slots inside or outside the resource pool.

For example, if the receiving UE transmits HARQ feedback on a PSFCHresource in response to one PSSCH transmitted by the transmitting UE tothe receiving UE, the receiving UE may determine a frequency domainand/or code domain of the PSFCH resource based on an implicit mechanismin a configured resource pool. For example, the receiving UE maydetermine the frequency domain and/or code domain of the PSFCH resource,based on at least one of a slot index related to PSCCH/PSSCH/PSFCH, asub-channel related to PSCCH/PSSCH, and/or an identifier for identifyingeach receiving UE in a group for HARQ feedback based on the groupcastoption 2. Additionally/alternatively, for example, the receiving UE maydetermine the frequency domain and/or code domain of the PSFCH resource,based on at least one of SL RSRP, SINR, L1 source ID, and/or locationinformation.

For example, if HARQ feedback transmission through the PSFCH of the UEand HARQ feedback reception through the PSFCH overlap, the UE may selectany one of HARQ feedback transmission through the PSFCH and HARQfeedback reception through the PSFCH based on a priority rule. Forexample, the priority rule may be based on at least priority indicationof the related PSCCH/PSSCH.

For example, if HARQ feedback transmission of a UE through a PSFCH for aplurality of UEs overlaps, the UE may select specific HARQ feedbacktransmission based on the priority rule. For example, the priority rulemay be based on at least priority indication of the related PSCCH/PSSCH.

Hereinafter, sidelink control information (SCI) will be described.

Control information transmitted by a BS to a UE through a PDCCH may bereferred to as downlink control information (DCI), whereas controlinformation transmitted by the UE to another UE through a PSCCH may bereferred to as SCI. For example, the UE may know in advance a startsymbol of the PSCCH and/or the number of symbols of the PSCCH, beforedecoding the PSCCH. For example, the SCI may include SL schedulinginformation. For example, the UE may transmit at least one SCI toanother UE to schedule the PSSCH. For example, one or more SCI formatsmay be defined.

For example, a transmitting UE may transmit the SCI to a receiving UE onthe PSCCH. The receiving UE may decode one SCI to receive the PSSCH fromthe transmitting UE.

For example, the transmitting UE may transmit two consecutive SCIs(e.g., 2-stage SCI) to the receiving UE on the PSCCH and/or the PSSCH.The receiving UE may decode the two consecutive SCIs (e.g., 2-stage SCI)to receive the PSSCH from the transmitting UE. For example, if SCIconfiguration fields are divided into two groups in consideration of a(relatively) high SCI payload size, SCI including first SCIconfiguration field group may be referred to as first SCI or 1^(st) SCI,and SCI including second SCI configuration field group may be referredto as second SCI or 2^(nd) SCI. For example, the transmitting UE maytransmit the first SCI to the receiving UE through the PSCCH. Forexample, the transmitting UE may transmit the second SCI to thereceiving UE on the PSCCH and/or the PSSCH. For example, the second SCImay be transmitted to the receiving UE through an (independent) PSCCH,or may be transmitted in a piggyback manner together with data throughthe PSSCH. For example, two consecutive SCIs may also be applied todifferent transmissions (e.g., unicast, broadcast, or groupcast).

For example, the transmitting UE may transmit the entirety or part ofinformation described below to the receiving UE through the SCI. Herein,for example, the transmitting UE may transmit the entirety or part ofthe information described below to the receiving UE through the firstSCI and/or the second SCI.

-   -   PSSCH and/or PSCCH related resource allocation information,        e.g., the number/positions of time/frequency resources, resource        reservation information (e.g., period), and/or    -   SL CSI report request indicator or SL (L1) RSRP (and/or SL (L1)        RSRQ and/or SL (L1) RSSI) report request indicator, and/or    -   SL CSI transmission indicator (or SL (L1) RSRP (and/or SL (L1)        RSRQ and/or SL (L1) RSSI) information transmission indicator))        (on PSSCH), and/or    -   MCS information, and/or    -   Transmit power information, and/or    -   L1 destination ID information and/or L1 source ID information,        and/or    -   SL HARQ process ID information, and/or    -   New data indicator (NDI) information, and/or    -   Redundancy version (RV) information, and/or    -   (Transmission traffic/packet related) QoS information, e.g.,        priority information, and/or    -   SL CSI-RS transmission indicator or information on the number of        (to-be-transmitted) SL CSI-RS antenna ports, and/or    -   Location information of a transmitting UE or location (or        distance region) information of a target receiving UE (for which        SL HARQ feedback is requested), and/or    -   Reference signal (e.g., DMRS, etc.) related to channel        estimation and/or decoding of data to be transmitted through a        PSSCH, e.g., information related to a pattern of a        (time-frequency) mapping resource of DMRS, rank information,        antenna port index information

For example, the first SCI may include information related to channelsensing. For example, the receiving UE may decode the second SCI byusing a PSSCH DMRS. A polar code used in a PDCCH may be applied to thesecond SCI. For example, in a resource pool, a payload size of the firstSCI may be identical for unicast, groupcast, and broadcast. Afterdecoding the first SCI, the receiving UE does not have to perform blinddecoding of the second SCI. For example, the first SCI may includescheduling information of the second SCI.

Meanwhile, in various embodiments of the present disclosure, since atransmitting UE may transmit at least one of SCI, first SCI, and/orsecond SCI to a receiving UE through a PSCCH, the PSCCH may bereplaced/substituted with at least one of the SCI, the first SCI and/orthe second SCI. Additionally/alternatively, for example, the SCI may bereplaced/substituted with at least one of the PSCCH, the first SCI,and/or the second SCI. Additionally/alternatively, for example, since atransmitting UE may transmit second SCI to a receiving UE through aPSSCH, the PSSCH may be replaced/substituted with the second SCI.

In the present disclosure, the term “configuration/configured ordefinition/defined” may be interpreted as being (pre-)configured fromthe base station or the network (through predefined signaling (e.g.,SIB, MAC signaling, RRC signaling)). For example, “A may be configured”may include “that the base station or the network(pre-)configures/defines or informs A to the UE”. Alternatively, theterm “configuration/configured or definition/defined” may be interpretedas being pre-configured or pre-defined in the system. For example, “Amay be configured” may include “that A is pre-configured/defined in thesystem”.

In the present disclosure, for example, a resource block (RB) may bereplaced/substituted with a subcarrier. Also, for example, in thepresent disclosure, a packet or traffic may be replaced/substituted witha transport block (TB) or a medium access control protocol data unit(PDU) according to a transmitted layer.

In the present disclosure, for example, a source ID may bereplaced/substituted with a destination ID.

In the present disclosure, for example, an L1 ID may bereplaced/substituted with an L2 ID. For example, the L1 ID may be an L1source ID or an L1 destination ID. For example, the L2 ID may be an L2source ID or an L2 destination ID.

Meanwhile, the base station may allocate resource(s) used fortransmission and reception of SL channel(s)/signal(s) (hereinafter, SLresource(s)) to the UE. For example, the base station may transmitinformation related to the resource(s) to the UE. In the presentdisclosure, a method in which the base station allocates SL resource(s)to the UE may be referred to as mode 1 method, mode 1 operation, orresource allocation mode 1.

On the other hand, the UE may select SL resource(s) within a resourcepool based on sensing. In the present disclosure, a method for selectingSL resource(s) by the UE may be referred to as a mode 2 method, a mode 2operation, or a resource allocation mode 2. For example, in the resourceallocation mode 2, the UE may detect SCI transmitted by other UE(s), andthe UE may identify resource(s) reserved by the other UE(s) based on theSCI, and the UE may obtain an RSRP measurement value. In addition, basedon the above-described sensing result, the UE may select resource(s) tobe used for SL transmission excluding specific resource(s) within aresource selection window. In the case of the sensing operation, the UEmay refer to resource allocation information received through first SCI.However, due to an overhead of the first SCI, the amount of informationthat can be obtained by the UE in the first SCI may be limited.

Based on various embodiments of the present disclosure, in order toassist a sensing operation and/or a resource selection operation of afirst UE, a second UE may transmit additional assistance information.The first UE may use assistance information received from the second UEin order to improve PSSCH detection performance and/or reducehalf-duplex limitation and/or select spare resource(s) for transmissionand reception of specific signal(s). In an embodiment of the presentdisclosure, for convenience of description, it is assumed that a UE-Atransmits assistance information to a UE-B. It is assumed that the UE-Bselects resource(s) for PSCCH/PSSCH to be transmitted to the UE-A and/orresource(s) for PSCCH/PSSCH to be transmitted to a UE-C (i.e., a thirdUE) based on the assistance information received from the UE-A.

FIG. 11 shows a procedure for a UE-A to transmit assistance informationto a UE-B, based on an embodiment of the present disclosure. Theembodiment of FIG. 11 may be combined with various embodiments of thepresent disclosure.

Referring to FIG. 11 , in step S1100, the UE-A may transmit assistanceinformation to the UE-B. For example, the UE-B may select resource(s)for PSCCH/PSSCH to be transmitted to the UE-A, based on assistanceinformation received from the UE-A, and the UE-B may perform SLtransmission by using the resource(s). For example, the UE-B may selectresource(s) for PSCCH/PSSCH to be transmitted to the UE-C based onassistance information received from the UE-A, and the UE-B may performSL transmission by using the resource(s). In the present disclosure,assistance information may be referred to as additional information.

Based on an embodiment of the present disclosure, information related toreserved resource(s) to be notified by the UE-A to the UE-B may beextended. For example, the assistance information may includeinformation related to additional resource(s) in addition to informationrelated to resource(s) included in SCI. For example, information relatedto resource(s) included in the assistance information may be informationrelated to extended reserved resource(s). Specifically, for example, theUE-A may transmit information related to other reserved resource(s)(e.g., information related to frequency domain resource(s) and/orinformation related to time domain resource(s)) to the UE-B throughassistance information, in addition to information related to reservedresource(s) (e.g., up to three resources) transmitted through the SCI.In this case, for the additionally indicated reserved resource(s), theUE-B may determine whether to exclude resource(s) corresponding to thereserved resource(s) within a resource selection window.

For example, the UE-A may select the extended reserved resource(s),through a resource (re)selection procedure, based on at least one of thenumber of retransmissions, whether or not it is retransmission, the sizeof a packet, the number of subchannels (or transmission unit) for PSSCHtransmission, a resource reservation period, priority information,and/or information related to a TB from a higher layer (e.g., MAClayer). Herein, the UE-A may perform a sensing operation, and when theUE-A performs a resource (re)selection procedure for each resource groupor (re)selects resource(s), the size of the corresponding window and/orthe number of resources may be extended. For example, the size of thewindow may be configured or pre-configured for the UE. For example,whether or not the size of the window is extended may be configured orpre-configured for the UE. For example, the (maximum) number ofresources may be configured or pre-configured for the UE. For example,whether or not the (maximum) number of resources is extended may beconfigured or pre-configured for the UE.

For example, the UE-A may transmit additional information (for selectedresources of the UE-A) when a PSCCH/PSSCH is transmitted in everyselected resource. Although the signaling overhead may be excessive inthe above case, it may be advantageous in that the UE-B can receive andutilize additional information in other time even if the UE-B does notdetect additional information.

For example, the UE-A may transmit additional information (for selectedresources of the UE-A) after the UE-A determines the selected resourcesthrough a resource (re)selection procedure. For example, the UE-A maytrigger transmission of additional information at a time of triggeringthe resource (re)selection procedure or after a specific time from thetime. For example, the specific time may be a pre-defined value or avalue (pre-)configured for the UE. In this case, for example, the UE-Amay transmit additional information in the initial resource of theselected resources. In the above case, signaling overhead can beminimized, but if the UE-B does not detect initial transmission, theUE-B may not be able to obtain additional information. Or, for example,the UE-A may transmit additional information in some of the selectedresources. For example, the UE-A may transmit additional information inN resources prior in time among the selected resources. The value of Nmay be a value configured through PC5-RRC signaling or a value(pre-)configured for the UE. For example, the UE-A may transmitadditional information in every M-th resource from the initial resourceamong the selected resources. The value of M may be a value configuredthrough PC5-RRC signaling or a value (pre-)configured for the UE.

For example, when additional information is transmitted, the UE-A maytransmit other MAC PDU or TB in addition to the additional information.For example, the additional information may be jointly encoded withother MAC PDU or TB. For example, the additional information may beencoded separately from other MAC PDU or TB.

For example, when additional information is transmitted, the UE-A maynot transmit other MAC PDU or TB in addition to the additionalinformation. In this case, for example, if additional information istransmitted through second SCI, the PSSCH may include only the secondSCI. In this case, for example, the number of subchannels may bedifferent between a PSSCH for transmitting additional information and aPSSCH for transmitting a general TB, and a resource selection window fortransmitting the additional information may exist separately (from aresource selection window for transmitting the general TB). Or, forexample, a resource selection window may be shared between a PSSCH fortransmitting additional information and a PSSCH for transmitting ageneral TB, and the resource selection window may be partitioned for theadditional information and the general TB. In this case, a priorityvalue of the PSSCH for the additional information may be a priorityvalue of a MAC PDU corresponding to a selected resource indicated by theadditional information. For example, a priority value of the PSSCH forthe additional information may be the minimum value among priorityvalues for the corresponding resource pool or the correspondingresource. For example, a priority value of the PSSCH for the additionalinformation may be the maximum value among priority values for thecorresponding resource pool or the corresponding resource. For example,a priority value of the PSSCH for the additional information may be avalue (pre-)configured for the corresponding resource pool or thecorresponding resource.

For example, the UE-A may transmit first SCI and/or additionalinformation, and the UE-B may transmit a response to the UE-A. Forexample, multiple UE may receive first SCI and/or additional informationtransmitted by the UE-A, and multiple UEs may respond to the first SCIand/or the additional information based on a common resource. Forexample, the response method may adopt the method of groupcast HARQ-ACKfeedback option 1. For example, a UE that receives a PSSCH for first SCIand/or additional information from the UE-A may select a PSFCH resourceassociated with the PSSCH, and the UE may determine whether to performPSFCH transmission based on the PSFCH resource. In this case, forexample, if the UE-B successfully receives the PSSCH for the first SCIand/or the additional information, the UE-B may omit PSFCH transmission.For example, if the UE-B receives only SCI (e.g., first SCI and/orsecond SCI), the UE-B may transmit a PSFCH. For example, if additionalinformation is transmitted through second SCI, even if the UE-B onlysuccessfully detects the SCI, the UE-B may transmit a PSFCH. Or, forexample, if the UE-B is allowed to use a resource indicated by theadditional information by the UE-A, the UE-B may omit PSFCHtransmission. For example, if the UE-B does not want a resourceindicated by the additional information to be used by the UE-A (e.g., ifthe resource overlaps with UE-B's selected resource and/or if theresource overlaps with SCI received by the UE-B and/or if theinterference level is determined to be a certain level or higher), theUE-B may transmit a PSFCH. Meanwhile, if the UE-B fails to detect SCIscheduling a PSSCH for additional information, the UE-B may omit PSFCHtransmission, and the UE-A may still determine that the interferencelevel in the resource is low, and the UE-A may use the resource.

For example, the UE-A may include all or part of information related toselected resources in a resource selection window in additionalinformation. In this case, for example, if the UE-A transmits additionalinformation for all or part of selected resources of the UE-A, theadditional information may always include information related to allselected resources. According to this method, resources from the pastmay be indicated based on the timing at which the additional informationis transmitted, and in the case of periodic traffic, the UE-B canconsider resources of the next reservation period of the past resourcesin the resource selection. More specifically, selected resourcesindicated by the initial first SCI may be excluded from selectedresources of the UE-A included in additional information. For example,the UE-A may transmit additional information in selected resources forother TBs within a resource selection window. This is because the UE-Atransmits the corresponding resource information in other PSCCH/PSSCHsthat are transmitted even if a problem occurs for all selected resourcesfor a specific TB (e.g., reception quality is below a certain level).

For example, the UE-A may include information related to some ofselected resources in a resource selection window in additionalinformation. For example, the UE-A may not include information relatedto selected resources before a time when the additional information istransmitted. For example, selected resources indicated by first SCI maybe excluded from the additional information. For example, informationrelated to selected resources after a certain time from the time whenthe additional information is transmitted may not be included in theadditional information. For example, the certain time may be a(pre-)configured value. In this case, the UE-A may update additionalinformation each time the UE-A sends the additional information and, asa result, the UE-A may also perform encoding again. For example, theadditional information may be encoded separately from a TB. For example,the additional information may be indicated by second SCI. For example,the additional information may be jointly encoded with a TB, and in thiscase, whether or not to transmit additional information may be differentin units of TB. In this case, for example, a value of additionalinformation may not change for a specific TB, and the value ofadditional information may change for the next TB or transmission ofadditional information may be omitted.

For example, a payload size for additional information may be predefinedor (pre-)configured, and the amount of information to be transmitted bythe UE-A may not fit the payload size. In this case, for example, if theamount of information to be transmitted by the UE-A is greater than thepayload size, the UE-A may omit transmission of some information amonginformation related to selected resources. For example, informationrelated to selected resources for which transmission is omitted may beinformation related to resources late in time. For example, the unit oftransmission omission may be a unit of an indicated resource (group), orsome bits of the resource indicator may be omitted. For example, if theamount of information to be transmitted by the UE-A is less than thepayload size, the UE-A may add padding bits (e.g., ALL-ZERO or ALL-ONE).

Meanwhile, the UE-A may transmit additional information includinginformation regarding selected resources of the UE-A. In this case,there may occur a case in which the UE-A cannot use the correspondingselected resources before indication the selected resources throughfirst SCI. For example, if selected resources indicated by the UE-Athrough additional information is occupied by another received SCI,and/or if an RSRP measurement value corresponding to the received SCI isgreater than or equal to an RSRP threshold, and/or if a receptionpriority value indicated by the received SCI is less than a transmissionpriority value of the UE-A, and/or if a reception priority valueindicated by the received SCI is less than a (pre-)configured prioritythreshold value, the UE-A may reselect all or part of the selectedresources.

For example, before the UE-A indicates selected resources through firstSCI or additional information, if the selected resources overlap with areserved resource indicated by received SCI, and if an RSRP measurementvalue corresponding to the received SCI is greater than or equal to anRSRP threshold, the UE-A may report resource re-evaluation for theselected resources. For example, after the UE-A indicates selectedresources through first SCI or additional information, if the selectedresources overlap with a reserved resource indicated by received SCI,and if an RSRP measurement value corresponding to the received SCI isgreater than or equal to an RSRP threshold, and if a reception priorityvalue indicated by the received SCI is less than a transmission priorityvalue of the UE-A, and if a reception priority value indicated by thereceived SCI is less than a (pre-)configured priority threshold value,the UE-A may report pre-emption for the selected resources.

For example, before the UE-A indicates selected resources through firstSCI or additional information, if the selected resources overlap with areserved resource indicated by received SCI, and if an RSRP measurementvalue corresponding to the received SCI is greater than or equal to anRSRP threshold, the UE-A may report resource re-evaluation for theselected resources. For example, after the UE-A indicates selectedresources through first SCI, if the selected resources overlap with areserved resource indicated by received SCI, and if an RSRP measurementvalue corresponding to the received SCI is greater than or equal to anRSRP threshold, and if a reception priority value indicated by thereceived SCI is less than a transmission priority value of the UE-A, andif a reception priority value indicated by the received SCI is less thana (pre-)configured priority threshold value, the UE-A may reportpre-emption for the selected resources. For example, before the UE-Aindicates selected resources through first SCI, if the selectedresources indicated through additional information overlap with areserved resource indicated by received SCI, and if an RSRP measurementvalue corresponding to the received SCI is greater than or equal to anRSRP threshold, and if a reception priority value indicated by thereceived SCI is less than a transmission priority value of the UE-A, andif a reception priority value indicated by the received SCI is less thana (pre-)configured priority threshold value, the UE-A may report a thirdstate (e.g., quasi-pre-emption) for the selected resources. For example,before the UE-A indicates selected resources through first SCI, if theselected resources indicated through additional information overlap witha reserved resource indicated by received SCI, and if an RSRPmeasurement value corresponding to the received SCI is greater than orequal to an RSRP threshold, the UE-A may report a third state (e.g.,quasi-pre-emption) for the selected resources. For example, before theUE-A indicates selected resources through first SCI, if the selectedresources indicated through additional information overlap with areserved resource indicated by received SCI, and if an RSRP measurementvalue corresponding to the received SCI is greater than or equal to anRSRP threshold, and if a reception priority value indicated by thereceived SCI is less than a transmission priority value of the UE-A, theUE-A may report a third state (e.g., quasi-pre-emption) for the selectedresources. For example, if the UE-A reports re-evaluation and/orpre-emption and/or quasi-pre-emption for a specific resource, the UE-Amay replace the corresponding resource with another resource amongavailable resources. For example, if the UE-A reports re-evaluationand/or pre-emption and/or quasi-pre-emption for a specific resource, theUE-A may replace all or part of selected resources of the UE-A withother resource(s) among available resources.

Meanwhile, in case that the UE-A indicates a selected resource throughadditional information, the UE-A may reselect the selected resourcebefore actual transmission occurs or before indicating the selectedresource through first SCI. In the above situation, the UE-A needs todetermine whether to change additional information according to thechanged information on the selected resource. For example, even if theselected resource is changed in the middle, the UE-A may maintainadditional information as it is. In particular, this is because whenadditional information is included in a TB, HARQ combining gain may notbe obtained if the additional information is changed. In addition,depending on the factor by which the UE-A changes the selected resource(e.g., another PSCCH/PSSCH occupies the corresponding resource), it maybe useful for the UE-B to avoid the resource indicated by the additionalinformation. For example, upon receiving additional information, theUE-B may prioritize a reserved resource indicated by first SCI. That is,if the UE-B recognizes that a resource indicated by additionalinformation is reselected based on received first SCI, the UE-B may notconsider the resource indicated by the additional information inresource selection of the UE-B. For example, regardless of whether theUE-A actually updates selected resources, the UE-B which has receivedadditional information may use selected resources indicated byadditional information to determine available resources of the UE-B. Forexample, regardless of whether the UE-A actually updates selectedresources, the UE-B which has received additional information maydetermine available resources of the UE-B based on information relatedto selected resources included in the additional information.

For example, if selected resources of the UE-A is changed in the middle,the UE-A may change additional information according to thecorresponding update information. For example, when selected resourcesof the UE-A is changed, the UE-A may transmit additional informationagain. For example, the UE-A may not include a resource excluded fromthe selected resources in the additional information, and the UE-A mayinclude a resource added as the selected resources in the additionalinformation.

For example, the UE-B may perform resource (re)selection based onadditional information whenever the UE-B receives additionalinformation. Whether or not additional information can be receivedand/or whether or not a resource (re)selection procedure is performed byusing additional information may be (pre-)configured for the UE-B.

For example, even if the UE-B receives assistance information, the UE-Bmay not perform resource (re)selection based on the received assistanceinformation in a specific situation. For example, the specific situationmay include a case in which the UE-B has already received additionalinformation. For example, the specific situation may include a case inwhich the UE-B has already received additional information and resourcesindicated by the additional information and the currently receivedadditional information are the same. For example, the specific situationmay include a case in which the UE-B has already received additionalinformation and resources indicated by the additional information are asubset of resources indicated by the currently received additionalinformation. For example, the specific situation may include a case inwhich the UE-B has already received additional information and resourcesindicated by the additional information are a superset of resourcesindicated by the currently received additional information. For example,the specific situation may include a case in which the UE-B has alreadyreceived additional information and a certain time has not elapsed sincethe UE-B performed resource (re)selection using the additionalinformation. For example, the certain time may be a value(pre-)configured for each resource pool. For example, the certain timemay be a value (pre-)configured for each TX priority pool. For example,the certain time may be a value (pre-)configured for each RX prioritypool. In this case, for example, the UE-B may check the time from thetime when determining selected resources through resource (re)selection.For example, the UE-B may check the time from the end of a slot in whichthe additional information is received.

Meanwhile, the UE-B which has received additional information may beinstructed again through first SCI at a different time, for selectedresources/reserved resources indicated by the additional information. Inthis case, UE-B may measure RSRP based on a PSSCH DMRS corresponding tothe first SCI for the reserved resources again, and considering thetime-varying channel environment and interference environment, the UE-Bmay use the updated RSRP measurement value that reflects theinterference environment more accurately than the additional informationindication time. For example, even if a resource was included inavailable resources based on additional information when the UE-Bperforms resource (re)selection, if an RSRP measurement value for theresource is greater than or equal to an RSRP threshold at the time ofreceiving the first SCI, the UE-B may exclude the resource fromavailable resources. This is because the UE-B determines that theinterference level is higher at the time of receiving the first SCI.Conversely, for example, even if a resource is not included in availableresources based on additional information when the UE-B performsresource (re)selection, an RSRP measurement value for the resource maybe less than or equal to an RSRP threshold at the time of receiving thefirst SCI. In this case, for example, the UE-B may determine that theinterference level for the resource has decreased at the time ofreceiving the first SCI, and the UE-B may include the resource inavailable resources of the UE-B again. Or, for example, the UE-B maystill maintain a state in which the resource is excluded from availableresources of the UE-B.

For example, the UE-B may determine whether to include or exclude thecorresponding resource from available resources of the UE-B, by using anRSRP measurement value for the corresponding resource used whenperforming resource (re)selection based on additional information and anRSRP measurement value for the corresponding resource at the time ofreceiving first SCI. For example, if the average (or weighted average)of the RSRP measurement values is greater than or equal to an RSRPthreshold, the UE-B may exclude the resource from available resources.For example, if the average (or weighted average) of the RSRPmeasurement values is less than an RSRP threshold, the UE-B may includethe resource in available resources. The RSRP threshold may be differentfrom an RSRP threshold used for resource (re)selection based on firstSCI. For example, the RSRP threshold may be an average (or weightedaverage) of an RSRP threshold used for resource (re)selection based onfirst SCI and an RSRP threshold used for resource (re)selection based onadditional information.

For example, the UE-B may determine whether to include or exclude thecorresponding resource from available resources of the UE-B according toa priority value for reserved resources indicated by additionalinformation or first SCI and a transmission priority value of the UE-B.For example, if the priority value for reserved resources indicated bythe additional information or the first SCI is less than thetransmission priority value of the UE-B and/or if the priority value forreserved resources indicated by the first SCI is less than a(pre-)configured threshold (and if an RSRP measurement value for thecorresponding resource used when performing resource (re)selection basedon the additional information and/or an RSRP measurement value for thecorresponding resource at the time of receiving the first SCI is greaterthan (each) RSRP threshold), the UE-B may exclude the correspondingresource from available resources of the UE-B.

Meanwhile, the UE-B which has received additional information from theUE-A may fail to detect first SCI in a selected resource/reservedresource indicated by the additional information. This may be a case inwhich the UE-A reselects the corresponding resource, or a case in whichthe first SCI reception performance is poor. Or, this may be a case inwhich the UE-B fails to perform the first SCI detection attempt due tohalf-duplex restriction.

For example, (Operation-A) if the UE-B does not detect first SCI on theselected resource/reserved resource indicated by additional information,the UE-B may include the corresponding resource in available resources.That is, the corresponding resource may not be considered when selectingresources excluded from a resource selection window.

For example, (Operation-B) even if the UE-B does not detect first SCI onthe selected resource/reserved resource indicated by additionalinformation, the UE-B may still not include the corresponding resourcein available resources. That is, the corresponding resource may beconsidered when selecting resources excluded from a resource selectionwindow. For example, if the UE-B does not detect first SCI in a specificslot (e.g., due to transmission of the UE-B), the UE-B may notselect/configure/determine, as excluded resources within a resourceselection window, all (frequency domain) resources belonging to all orpart of slots (e.g., slots after resource reservation periods from thespecific slot) derived based on all or part of resource reservationperiod candidate values (e.g., resource reservation period candidatevalues greater than or equal to 100 msec or 20 msec among resourcereservation period candidate values) configured for a resource pool ofthe UE-B and the specific slot. That is, for example, the UE-B mayselect/configure/determine, as excluded resources, only resourcesdetermined based on the additional information among all (frequencydomain) resources belonging to all or part of slots (e.g., slots afterresource reservation periods from the specific slot). In other words,for example, the UE-B may determine a reception pattern related to thespecific slot, based on resource information indicated in additionalinformation received by the UE-B in another slot and/or an RSRPmeasurement value corresponding to the resource information. In thiscase, for example, if the reception pattern overlaps with a transmissionpattern determined based on transmission resource reservation period(s)and a transmission resource reselection counter of the UE-B, the UE-Bmay exclude the transmission pattern or a combination of a startingsubchannel and/or a slot of the transmission pattern from a set ofavailable resources.

For example, (Operation-C) if the UE-B does not detect first SCI in aspecific slot (e.g., due to transmission of the UE-B), the UE-B mayselect/configure/determine, as excluded resources within a resourceselection window, all (frequency domain) resources belonging to all orpart of slots (e.g., slots after resource reservation periods from thespecific slot) derived based on all or part of resource reservationperiod candidate values (e.g., resource reservation period candidatevalues greater than or equal to 100 msec or 20 msec among resourcereservation period candidate values) configured for a resource pool ofthe UE-B and the specific slot. In other words, for example, if (i)feasible reception pattern(s) determined based on resource reservationperiod candidate values from the specific slot and (ii) a transmissionpattern determined based on transmission resource reservation period(s)and a transmission resource reselection counter of the UE-B overlap, theUE-B may exclude the transmission pattern or a combination of a startingsubchannel and/or a slot of the transmission pattern from a set ofavailable resources.

For example, (Operation-D) if the UE-B does not detect first SCI in aspecific slot (e.g., due to transmission of the UE-B), the UE-B mayselect/configure/determine, as excluded resources within a resourceselection window, all frequency domain resources belonging to all orpart of slots (e.g., slots after resource reservation periods from thespecific slot) derived based on a specific resource reservation period(e.g., (pre-)configured resource reservation period(s) and transmissionresource reservation period(s) of the UE-B) and the specific slot. Inother words, for example, if (i) feasible reception pattern(s)determined based on the specific resource reservation period from thespecific slot and (ii) a transmission pattern determined based ontransmission resource reservation period(s) and a transmission resourcereselection counter of the UE-B overlap, the UE-B may exclude thetransmission pattern or a combination of a starting subchannel and/or aslot of the transmission pattern from a set of available resources.

For example, (Operation-E) the UE-B may exclude (i) a reception patternderived based on additional information and/or (ii) a transmissionpattern of the UE-B overlapping with a reception pattern derived basedon a specific resource reservation period according to (Operation-B) and(Operation-D) from a set of available resources of the UE-B.

For example, (Operation-F) the UE-B may exclude (i) a reception patternderived based on additional information and/or (ii) a transmissionpattern of the UE-B overlapping with a reception pattern derived basedon a specific resource reservation period according to (Operation-B) and(Operation-C) from a set of available resources of the UE-B. Forexample, UE-B may derive a set of slots corresponding to the specificslot (e.g., a slot in which SCI is not detected) from all or part ofresource reservation period candidate values. In this case, for example,the UE-B may perform (Operation-B) on slots to which resources indicatedin additional information belong among the set of slots, and the UE-Bmay perform (Operation-C) on slots to which resources indicated inadditional information does not belong among the set of slots.

For example, which of the above operations is to be performed by theUE-B may be (pre-)configured for each resource pool for the UE-B. Forexample, the base station/network may transmit information related to anoperation to be performed by the UE-B to the UE-B.

For example, UE-B may select (Operation-A), (Operation-B),(Operation-C), (Operation-D) or a combination of the operations, basedon a priority value corresponding to resources indicated by additionalinformation, a congestion control level, periodicity or aperiodicity,reception quality of additional information, and/or whether the UE-Breceives first SCI at the next resource location of the correspondingresource. For example, if a priority value for the correspondingresource is less than or equal to a specific threshold, the UE-B mayselect (Operation-B). Otherwise, the UE-B may select (Operation-A). Forexample, if a priority value for the corresponding resource is greaterthan or equal to a specific threshold, the UE-B may select(Operation-B), (Operation-D) or (Operation-E). For example, if apriority value for the corresponding resource is less than or equal to aspecific threshold, the UE-B may select (Operation-C). In this case, forexample, the threshold may be (pre-)configured to the UE for eachresource pool and/or for each congestion control level and/or for eachQoS parameter. For example, if a received RSRP value for additionalinformation is greater than or equal to a (pre-)configured threshold,the UE-B may select (Operation-B), (Operation-D) or (Operation-E). Forexample, if a CBR value is less than or equal to a (pre-)configuredthreshold, the UE-B may select (Operation-B), (Operation-D) or(Operation-E). For example, if a received RSRP value for additionalinformation is less than or equal to a (pre-)configured threshold, theUE-B may select (Operation-C). For example, if a CBR value is greaterthan or equal to a (pre-)configured threshold, the UE-B may select(Operation-C). For example, the operation method selected/performed bythe UE-B may be different based on a ratio of available resources toresources within a resource selection window. For example, when the UE-Bdetermines available resources based on (Operation-C), if the ratio ofavailable resources cannot exceed a (pre-)configured threshold, the UE-Bmay perform (Operation-B), (Operation-D) or (Operation-E).

Meanwhile, in a resource indicated in additional information, the UE-Amay indicate the groupcast HARQ feedback option 1, and the UE-B may failto detect the corresponding SCI (e.g., first SCI and/or second SCI). Inthe above case, the UE-B cannot transmit SL HARQ-ACK feedback for thecorresponding resource or PSSCH. In addition, the UE-A may determinethat the UE-B succeeded in decoding at the corresponding time and didnot transmit a PSFCH or SL HARQ-ACK feedback. In this case, because NACKis determined to be ACK, the latency time for a service received by theUE-B may increase or the reliability may decrease. For example, when theUE-A indicates the UE-B to select resources/reservation resourcesthrough additional information, the UE-A may also indicate a responsemethod (e.g., a cast type and/or a HARQ-ACK feedback option/method to beused in the corresponding resource) to the UE-B. Or, if the UE-Breceives additional information from the UE-A, the UE-B may determine acast type and a HARQ-ACK feedback option based on information indicatedin the corresponding SCI. For example, the UE-B may recognize that theresource indicated by additional information is used for the groupcastHARQ-ACK feedback option 1, and even if the UE-B does not receive firstSCI in the indicated resource, the UE-B may transmit NACK. In this case,a PSFCH resource to be used by the UE-B may be determined based on slotinformation or subchannel information of the resource indicated by theadditional information, and/or an L1-source ID indicated by SCIcorresponding to a channel used to transmit the additional information.

Based on an embodiment of the present disclosure, the UE-A may transmitall or part of information on a sensing operation performed by the UE-Ato the UE-B. For example, the assistance information may includeinformation obtained by the UE-A based on the sensing operation. Forexample, information on the sensing operation may include at least oneof information related to reserved resources indicated by first SCIand/or second SCI and/or a PSSCH detected by the UE-A, informationrelated to a priority, an L1-source-ID, an L1-destination-ID, a HARQprocess number and/or information related to an RSRP measurement value.For example, information on the sensing operation may includeinformation on a resource selection window of the UE-A and/orinformation on (all or part of) resources excluded from target resourcesto be selected based on sensing within the resource selection window.Herein, the UE-B may consider a resource indicated through SCI detectedby the UE-A but not detected by the UE-B when selecting a resource. Forexample, when the UE-B performs resource (re)selection, the UE-B may not(re)select a resource indicated through SCI detected by the UE-A but notdetected by the UE-B based on the above information. That is, based onthe above method, interference from a UE that the UE-B is not aware ofdue to a hidden-node problem can be minimized.

For example, the UE-A may transmit corresponding additional informationto the UE-B at a time when a PSSCH resource selection procedure istriggered or after a certain slot offset from the corresponding time.For example, the certain slot offset may be a predefined value. Forexample, the certain slot offset may be a value determined by the UE-A.For example, the certain slot offset may be a (pre-)configured value.For example, the UE-A may transmit corresponding additional informationto the UE-B at a time when selection/reservation resources or the UE-Aare determined or after a certain slot offset from the correspondingtime. For example, the certain slot offset may be a predefined value.For example, the certain slot offset may be a value determined by theUE-A. For example, the certain slot offset may be a (pre-)configuredvalue. In this case, the UE-A may distinguish available resources,excluded resources, and/or selected resources within a resourceselection window of the UE-A based on a sensing operation.

For example, the UE-A may trigger transmission of additional informationevery (pre-)configured period. In this case, for example, the period maybe applied to physical slots. For example, the period may be applied toslots (i.e., logical slots capable of SL communication) in which asymbol period corresponding to the number of SL symbols from an SL startsymbol is cell-specific uplink. For example, the period may be appliedto logical slots other than S-SSB slots in the logical slots capable ofthe SL communication. For example, the period may be applied to slotswithin a transmission resource pool and/or a reception resource pool.For example, the time when transmission of additional information withina period is triggered may be determined from a slot offset(pre-)configured for each resource pool. In this case, for example, theslot offset may be expressed as the number of physical slots withrespect to SFN0 or DFN0 as a reference point. For example, the slotoffset may be expressed as the number of corresponding logical slotswith respect to the first slot of the logical slots capable of SLcommunication within an SFN cycle or a DFN cycle as a reference point.For example, the slot offset may be expressed as the number of logicalslots excluding S-SSB slots with respect to the first slot of thelogical slots capable of the SL communication excluding S-SSB slots inan SFN cycle or an DFN cycle as a reference point. For example, the slotoffset may be expressed as the number of corresponding logical slotswith respect to the first slot of the logical slots belonging to aresource pool within a resource pool period as a reference point. Forexample, the period and/or the time when transmission of additionalinformation is triggered may be associated with an SL DRX operationcycle of the UE. For example, in the SL DRX operation, a minimum periodin which the UE attempts SCI detection and a period in whichtransmission of additional information is triggered may be the same. Forexample, in the SL DRX operation, a period in which transmission ofadditional information is triggered may be configured as a multiple of aminimum period in which the UE attempts SCI detection.

For example, under a specific condition, the UE-A may skip triggering oftransmission of additional information in a specific period. Forexample, under a specific condition, the UE-A may skip transmission ofadditional information in a specific period. For example, the specificcondition may be a case in which reception quality of transmission bythe UE-B from the perspective of the UE-A is equal to or higher than acertain level. For example, the UE-A may determine the reception qualityby comparing an RSRP measurement value measured based on RS transmittedby the UE-B with a (pre-)configured threshold. For example, the UE-A maydetermine the reception quality by comparing an RSSI measurement valuefor a resource occupied by an SL channel transmitted by the UE-B with a(pre-)configured threshold. For example, based on whether the UE-Asuccessfully decodes a PSSCH received from the UE-B, the UE-A maydetermine the reception quality. For example, based on whether the UE-Afails to decode a PSSCH received from the UE-B, the UE-A may determinethe reception quality. For example, based on a ratio of successfuldecoding of a PSSCH received by the UE-A from the UE-B, the UE-A maydetermine the reception quality. For example, based on a ratio of faileddecoding of a PSSCH received by the UE-A from the UE-B, the UE-A maydetermine the reception quality. For example, the specific condition maybe a case in which the UE-A does not observe a case in which an RSRPmeasurement value for an SL channel having a specific priority is equalto or greater than a (pre-)configured threshold. For example, thespecific condition may be a case in which the UE-A does not change allor part of indicated resources included in additional information. Forexample, the specific condition may be a case in which resources aftertransmitting additional information do not change. For example, triggerconditions of additional information of the UE-A may be configured as acombination of trigger conditions of additional information in anotherembodiment of the present disclosure.

For example, the UE-A may receive a request for additional information(hereinafter, additional information request, additional informationrequest information or request) from the UE-B. In this case, the UE-Amay transmit additional information after a certain slot offset from atime of receiving the request for additional information from the UE-B.For example, the UE-A may transmit additional information at a specifictime after the UE-B requests additional information. Or, for example,the UE-A may transmit additional information within a specific windowafter the UE-B requests additional information. For example, theadditional information request transmitted by the UE-B may include atleast one of reference transmission priority information, a resourcedomain of interest (e.g., a reference resource selection window), areference resource reservation period, a reference resource reselectioncounter, the number of retransmissions, the maximum number ofretransmissions, the reference number of subchannels for PSSCHtransmission, a cast type, a service type, packet delay budget (PDB)information for additional information, reference PDB information,presence or absence of SL HARQ feedback, a QoS parameter, and/or a typeof additional information (e.g., preferred resource, non-preferredresource, operation of receiving additional information, method of usingadditional information, etc.). In this case, for example, the UE-A maygenerate/configure additional information based on request informationof the UE-B. For example, the (start) location of a resource windowcorresponding to additional information may be determined based on atime when the UE-A detects the request or a time when the UE-B transmitsthe request. For example, additional information request information mayinclude a (slot) offset value between a time when the additionalinformation request is transmitted and the (start) location of theresource window to be used for the additional information. For example,the UE-A may recognize when transmission of additional informationshould be completed based on PDB for the additional information of theUE-B. For example, upon receiving a request for additional informationfrom the UE-B, the UE-A may ignore the request from the UE-B and skiptransmission of additional information in a specific situation. Forexample, the specific situation may include a case in which the UE-Adoes not have a sensing result for a reference transmission priorityand/or a reference resource reservation period included in the requestof the UE-B. For example, the specific situation may include a case inwhich a first time when the UE-A detects the request of the UE-B haspassed a second time determined based on reference PDB information, theremaining PDB of the UE-B, or PDB information for the additionalinformation. For example, the specific situation may include a case inwhich the difference between the first time and the second time is lessthan or equal to a (pre-)configured/defined threshold. For example, thespecific situation may include a case in which the UE-A does not haveinformation on available resources, excluded resources, and/or selectedresources within the reference resource selection window included in therequest of the UE-B. For example, the specific situation may include acase in which a target UE for the request of the UE-B is not the UE-A.For example, the specific situation may include a case in which an RSRPmeasurement value measured by the UE-A based on a signal or a channelfor the request of the UE-B is less than or equal to a (pre-)configuredthreshold. For example, the specific situation may include a case inwhich the UE-A fails to generate additional information related to acast type requested by the UE-B. For example, the specific situation mayinclude a case in which the UE-A does not support a cast type requestedby the UE-B. For example, the specific situation may include a case inwhich there is no unicast session between the UE-A and the UE-B (eventhough the request indicates it is for unicast). For example, the UE-Amay receive requests for additional information from a plurality of UEs,and the UE-A may generate additional information for the plurality ofUEs and transmit the additional information based on one physicalchannel (e.g., PSCCH/PSSCH). For example, even in the method without theadditional information request, the UE-A may generate additionalinformation for a plurality of UE and transmit the additionalinformation by using one physical channel.

For example, the additional information request may be transmittedthrough a PSCCH and/or a PSSCH. In this case, for example, a priority ofthe additional information request may be the same as a transmissionpriority of data/packet of the UE-B. Or, for example, a priority of theadditional information request may be a (pre-)configured value. Forexample, a source ID for the additional information request may be asource ID of the UE-B for a service corresponding to the UE transmittingthe request. For example, a source ID for the additional informationrequest may be (pre-)configured. For example, a source ID for theadditional information request may be configured through PC5-RRCsignaling. For example, a destination ID for the additional informationrequest may be configured through PC5-RRC signaling. For example, asource ID for the additional information request may be(pre-)configured.

For example, the additional information request may be transmitted inthe form of a PSFCH. For example, a PSFCH resource to be used for theadditional information request may be configured differently from aPSFCH resource for SL HARQ feedback. For example, PRB sets for eachPSFCH resource may be configured independently of each other. Forexample, a PSFCH resource for the additional information request may be(pre-)configured for each UE (group). For example, a PSFCH resource forthe additional information request may be configured through PC5-RRCsignaling for each UE (group). For example, a PSFCH resource for theadditional information request may be selected based on a source ID ofthe additional information request. For example, a PSFCH resource forthe additional information request may be commonly (pre-)configured forUEs. For example, which PSFCH state (e.g., ACK resource or NACKresource) will be used may be configured together with the PSFCHresource.

For example, a PSFCH resource for the additional information request maybe selected differently for each source ID (e.g., L1 source ID) for atransmission packet of the UE transmitting the request and/or priorityvalue for the transmission packet and/or buffer status for thetransmission packet and/or buffer status for the UE and/or amount ofremaining packets for the transmission packet and/or amount of resourcesrequested by the UE. For example, a PSFCH resource to be used for theadditional information request may be selected by a combination of theabove parameters. For example, the UE transmitting the additionalinformation request may select/determine a PSFCH resource for theadditional information request based on a source ID (e.g., L1 source ID)related to a transmission packet. For example, the UE transmitting theadditional information request may select/determine a PSFCH resource forthe additional information request based on a priority value related toa transmission packet. For example, the UE transmitting the additionalinformation request may select/determine a PSFCH resource for theadditional information request based on a buffer status related to atransmission packet. For example, the UE transmitting the additionalinformation request may select/determine a PSFCH resource for theadditional information request based on a buffer status of the UE. Forexample, the UE transmitting the additional information request mayselect/determine a PSFCH resource for the additional information requestbased on the amount of remaining packets related to a transmissionpacket. For example, the UE transmitting the additional informationrequest may select/determine a PSFCH resource for the additionalinformation request based on the amount of resources to be requested bythe UE.

For example, a specific RB set may be determined among PSFCH resourcesincluding a plurality of RB sets, based on the amount of remainingpackets corresponding to a transmission packet of the UE transmittingthe request and/or the number of subchannels to be requested and/or apriority value corresponding to the transmission packet. For example,the PSFCH resources may include a plurality of RB sets, and one RB setmay include one or more RBs. For example, the UE transmitting theadditional information request may select/determine a specific RB setfrom among PSFCH resources including a plurality of RB sets based on theamount of remaining packets corresponding to a transmission packet. Forexample, the UE transmitting the additional information request mayselect/determine a specific RB set from PSFCH resources including aplurality of RB sets based on the number of subchannels to be requested.For example, the UE transmitting the additional information request mayselect/determine a specific RB set from PSFCH resources including aplurality of RB sets based on a priority value corresponding to atransmission packet.

For example, a PSFCH RB and/or a cyclic shift value and/or a cyclicshift pair index value within the specific RB set value may bedetermined based on a source ID (e.g., L1 source ID) corresponding to atransmission packet of the UE transmitting the request. For example, theUE transmitting the additional information request may select/determineat least one of a PSFCH RB, a cyclic shift value, and/or a cyclic shiftpair index value within the specific RB set.

For example, even for the same UE, according to the amount of resourcesrequested for transmission packet information of the UE, the UE mayselect different PSFCH resources to transmit the additional informationrequest, and the UE may transmit the additional information requestbased on the selected PSFCH resource. For example, even for the same UE,for a case in which the amount of remaining packets is less or greater(than a threshold configured for the UE), the UE may select differentPSFCH resources to transmit the additional information request, and theUE may transmit the additional information request based on the selectedPSFCH resource. For example, the UE receiving the additional informationrequest may distinguish/determine a UE transmitting the request (byusing an L1 source ID) based on the detected PSFCH resource, and/or maydetermine the amount of resources to be allocated.

For example, a PSFCH resource for transmitting the additionalinformation request may be allocated for each UE group, and UEs in thesame group may share a PSFCH resource related to the additionalinformation request. Specifically, for example, the UE group may beconfigured for the UE through higher layer signaling (e.g., PC5-RRC,PC5S-RRC, MAC CE, AS layer signaling, and/or V2X layer signaling, etc.).For example, the UE may receive information related to the UE groupthrough higher layer signaling (e.g., PC5-RRC, PC5S-RRC, MAC CE, ASlayer signaling, and/or V2X layer signaling, etc.).

For example, the UE group may be determined based on a geographicdistance or direction between UEs receiving the additional informationrequest and/or location information of UEs. For example, the UE groupmay be determined based on RSRP values measured from UEs receiving theadditional information request. For example, the UE group may bedetermined based on a range of RSRP values measured from UEs receivingthe additional information request.

For example, if a UE within a UE group determines that a preferredresource derived based on additional information for the UE group ismore needed, the UE may transmit request signaling corresponding to theUE group to a UE transmitting additional information (e.g., a UE capableof transmitting additional information or a UE transmitting additionalinformation) or a UE receiving the additional information request. Forexample, if a UE within a UE group determines that a preferred resourcederived based on additional information for the UE group can be reduced,the UE may transmit request signaling corresponding to the UE group to aUE transmitting additional information (e.g., a UE capable oftransmitting additional information or a UE transmitting additionalinformation) or a UE receiving the additional information request. Forexample, the type or value of the request signaling may beconfigured/determined differently depending on whether the UE increasesor decreases preferred resources that can be derived based on additionalinformation for the UE group.

For example, whether or not the preferred resource is insufficient maybe determined depending on whether the ratio or number of availableresources derived based on additional information and/or sensinginformation of the UE within a resource (re)selection window in aresource (re)selection procedure by the UE is less than or equal to a(pre-)configured threshold. For example, if the ratio or number ofavailable resources derived by the UE based on additional informationand/or sensing information of the UE within the resource (re)selectionwindow is less than or equal to a (pre-)configured threshold, the UE maydetermine that the preferred resource is insufficient. For example, ifthe ratio or number of available resources derived by the UE based onadditional information and/or sensing information of the UE within theresource (re)selection window is greater than or equal to a(pre-)configured threshold, the UE may determine that the preferredresource is not insufficient (i.e., the preferred resource can bereduced).

For example, whether or not the preferred resource is insufficient maybe determined depending on whether the UE boosts an RSRP threshold for aresource selection procedure in the resource (re)selection procedure.For example, if the UE boosts the RSRP threshold for resource selectionin the process of performing resource (re)selection, the UE maydetermine that the preferred resource is insufficient. For example, ifthe UE does not boost the RSRP threshold for resource selection in theprocess of performing resource (re)selection, the UE may determine thatthe preferred resource is not insufficient (i.e., the preferred resourcecan be reduced).

For example, the UE transmitting additional information may receive aPSFCH related to an additional information request (i.e., a PSFCH forthe additional information request) from a single UE group or aplurality of UE groups. In this case, for example, the UE transmittingthe additional information may determine additional information for theUE group transmitting the additional information request according to aPSFCH type or a PSFCH value. For example, the UE transmitting theadditional information may determine to increase the amount of preferredresources for the UE group transmitting the additional informationrequest according to the PSFCH type or the PSFCH value. For example, theUE transmitting the additional information may determine to reduce theamount of preferred resources for the UE group transmitting theadditional information request according to the PSFCH type or the PSFCHvalue. For example, the UE transmitting the additional information maydetermine to maintain the amount of preferred resources for the UE grouptransmitting the additional information request according to the PSFCHtype or the PSFCH value.

For example, if the UE transmitting the additional information increasesthe amount of resources based on the additional information request, theUE may boost an RSRP threshold and then determine non-preferredresources based on sensing by using the boosted RSRP threshold. Forexample, if the UE transmitting the additional information reduces theamount of resources based on the additional information request, the UEmay de-boost an RSRP threshold and then determine non-preferredresources based on sensing by using the de-boosted RSRP threshold.

For example, a value which is a unit of boosting and/or de-boosting forthe RSRP threshold may be configured or pre-configured for the UE foreach resource pool. For example, a value which is a unit of boostingand/or de-boosting for the RSRP threshold may be configured orpre-configured for the UE for each reference transmission priority. Forexample, a value which is a unit of boosting and/or de-boosting for theRSRP threshold may be configured or pre-configured for the UE for eachreception priority included/indicated in SCI received by the UE. Forexample, a value which is a unit of boosting and/or de-boosting for theRSRP threshold may be configured or pre-configured for the UE for eachcongestion control level. For example, a value which is a unit ofboosting and/or de-boosting for the RSRP threshold may be configured orpre-configured for the UE for each UE group.

For example, the UE may determine whether boosting and/or de-boosting isapplied to the RSRP threshold and the number of boosting and/orde-boosting applied to the RSRP threshold only based on a requestimmediately before transmission of previous additional information. Forexample, the UE may determine whether boosting and/or de-boosting isapplied to the RSRP threshold and the number of boosting and/orde-boosting applied to the RSRP threshold by accumulating requestsimmediately before transmission of previous additional information. Forexample, if the UE transmitting additional information does not receivean additional information request during a specific time period, the UEmay cancel/reset boosting and/or de-boosting applied to the RSRPthreshold. For example, the specific time period may be configured orpre-configured for the UE for each resource pool. For example, thespecific time period may be configured or pre-configured for the UE foreach reference transmission priority. For example, the specific timeperiod may be configured or pre-configured for the UE for each receptionpriority included/indicated in SCI received by the UE. For example, thespecific time period may be configured or pre-configured for the UE foreach congestion control level. For example, the specific time period maybe configured or pre-configured for the UE for each UE group.

FIG. 12 shows a procedure for the UE-A to transmit assistanceinformation to the UE-B, based on an embodiment of the presentdisclosure. The embodiment of FIG. 12 may be combined with variousembodiments of the present disclosure.

Referring to FIG. 12 , in step S1200, for example, a UE transmitting anadditional information request may request resource allocationinformation and/or available resource information in the form of a PSFCHresource from a UE transmitting additional information.

In step S1210, for example, in order to obtain detailed information(e.g., additional request information or detailed information) relatedto the request from the UE transmitting the additional informationrequest, the UE receiving the additional information request maytransmit available or recommended resource information for PSCCH/PSSCHtransmission to the UE transmitting the request. For example, in orderto obtain detailed information (e.g., additional request information ordetailed information) related to the request from the UE transmittingthe additional information request, the UE receiving the additionalinformation request may transmit unavailable or unrecommended resourceinformation for PSCCH/PSSCH transmission to the UE transmitting therequest.

In step S1220, for example, the UE which has received resourceinformation regarding PSCCH/PSSCH for additional request informationfrom another UE may transmit a PSCCH/PSSCH based on the resourceinformation. Herein, for example, at least one of reference transmissionpriority information, resource domain of interest (e.g., referenceresource selection window), a reference resource reservation period, areference resource reselection counter, the number of retransmissions,the maximum number of retransmissions, the reference number ofsubchannels for PSSCH transmission, a cast type, a service type, PDBinformation for additional information, reference PDB information,presence or absence of SL HARQ feedback, a QoS parameter, and/or a typeof additional information (e.g., preferred resource, non-preferredresource, operation of receiving additional information, method of usingadditional information, etc.) may be transmitted through thePSCCH/PSSCH. For example, the reference parameters may be inherited fromparameters of a transmission packet of the UE which has transmitted thedetailed information related to the additional information request.

In step S1230, for example, the UE which has received the detailedinformation related to the additional information request mayprovide/transmit, to the UE transmitting the additional informationrequest, resource information (e.g., preferred resource information ornon-preferred resource information) that can be used for resourcereselection for data transmission by the UE transmitting the additionalinformation request, based on the reference parameter(s). For example,the UE receiving additional information may use the additionalinformation to (re)select a resource to be used for future datatransmission. That is, for example, the UE receiving additionalinformation may (re)select a resource to be used for future datatransmission based on the additional information.

For example, the process of transmitting the requested detailedinformation after transmitting the additional information request may beskipped in a specific situation. For example, the specific situation maybe a case in which the UE which has transmitted the additionalinformation request can transmit remaining packets only with theresource information received in response to the additional informationrequest (i.e., the resource information received in S1210). For example,the specific situation may be a case in which the remaining PDB for atransmission packet of the UE which has transmitted the additionalinformation request is less than or equal to a predefined or(pre-)configured threshold. For example, the specific situation may be acase in which the request procedure for the detailed information and/orthe transmission procedure for the detailed information is not(pre-)configured for the UE. In other words, the request for thedetailed information and/or the transmission of the detailed informationmay be performed by the UE only if the corresponding operation is(pre-)configured for the UE.

Meanwhile, PSFCH transmission and/or reception for SL HARQ feedback ofthe UE and PSFCH transmission and/or reception for an additionalinformation request of the UE may overlap in the same slot. In thiscase, for example, in simultaneous transmission, the UE needs to skipsome PSFCH transmissions. For example, when PSFCH transmission andreception overlap, the UE needs to perform only one operation. In thiscase, for example, the UE may determine a PSFCH to be transmitted orreceived according to a priority related to a PSFCH for the additionalinformation request. For example, a priority of PSFCH transmission andreception for SL HARQ feedback may be higher than a priority of PSFCHtransmission and reception for an additional information request. Forexample, a priority of PSFCH transmission and reception for SL HARQfeedback may be lower than a priority of PSFCH transmission andreception an additional information request. For example, a priority ofPSFCH transmission and/or reception for SL HARQ-ACK feedback and apriority of PSFCH transmission and/or reception related to additionalinformation may be determined based on a priority value corresponding toeach PSFCH. For example, a priority of a PSFCH for the additionalinformation request may be a priority value for a TX packet of the UEtransmitting the request. For example, in this case, a UE receiving thePSFCH may not know the priority value of the TX packet of the other UE.In this case, a priority value for PSFCH reception of the UE may be(pre-)configured. For example, a priority of a PSFCH for the additionalinformation (e.g., resource conflict indication) may be a priority valueof a PSSCH transmitted in a resource where the resource conflict occurs,which is the purpose of transmitting the additional information. Forexample, the priority value of the PSSCH corresponding to the resourceconflict may be obtained based on SCI received by the UE transmittingthe additional information. For example, if there are a plurality ofPSSCHs corresponding to the resource conflict, the UE transmitting theadditional information may inherit a priority value corresponding to aPSSCH transmitted by a UE targeted for the additional information,and/or may inherit the maximum priority value or the minimum priorityvalue for the plurality of PSSCHs. For example, from the point of viewof a UE expecting to receive the additional information, a priority of aPSFCH for the additional information may inherit a priority value of aPSSCH transmitted by the UE. For example, a priority value of a PSFCHrelated to the additional information may be (pre-)configured for eachresource pool and/or for each congestion control level. For example, apriority value of a PSFCH related to the additional information may be(pre-)configured separately for a case of PSFCH transmission and a caseof PSFCH reception. For example, specifically, when the UE determines apriority for PSFCH transmission and/or reception for SL HARQ-ACKfeedback and a priority for PSFCH transmission and/or reception relatedto additional information based on priority values, the UE maypreferentially select one operation from PSFCH transmission or PSFCHreception. For example, the UE may select one operation of PSFCHtransmission or PSFCH reception based on priority values of PSFCHtransmission and reception for SL HARQ-ACK feedback. For example, basedon priority values of PSFCH transmission and/or reception for SLHARQ-ACK feedback and priority values for PSFCH transmission and/orreception related to additional information, the UE may select anoperation (e.g., PSFCH transmission or PSFCH reception) corresponding toa smaller value between the minimum priority value for transmission andthe minimum priority value for reception. For example, if the minimumpriority value of the PSFCH transmission group and the minimum priorityvalue of the PSFCH reception group are the same, the UE may compare thenext highest priority value in each group. In addition, the UE mayperform an operation (e.g., PSFCH transmission or PSFCH reception)corresponding to the smaller value between the corresponding priorityvalue of transmission (i.e., the second smallest transmission priorityvalue) and the corresponding priority value of reception (i.e., thesecond smallest reception priority value). For example, the operation ofcomparing the next priority value may be extended to a form of comparingthe next priority value when the second priority value is the same. Forexample, if there is no next priority value for each group, for thegroup, the current priority value may be used for priority comparisonagain. For example, if it is determined that priorities of the PSFCHtransmission operation and the PSFCH reception operation are the same,the UE may select the PSFCH transmission operation if there is PSFCHtransmission related to the additional information, and the UE mayselect the PSFCH reception operation if there is PSFCH reception relatedto the additional information. For example, a set of PSFCH resourcesrelated to additional information may be configured separately from aset of PSFCH resources for SL HARQ-ACK feedback. In this case, an indexvalue for the set of PSFCH resources may be used when prioritizing PSFCHtransmission and reception. For example, after the UE selects a PSFCH ora PSFCH group based on a priority value of the PSFCH, for the samepriority, the UE may determine that the priority is higher as the indexvalue for the set of PSFCH resources is higher. For example, after theUE selects a PSFCH or a PSFCH group based on a priority value of thePSFCH, for the same priority, the UE may determine that the priority ishigher as the index value for the set of PSFCH resources is lower. Forexample, the UE may determine that the priority is higher as the indexvalue for the set of PSFCH resources is higher or lower, and then the UEmay determine a priority for PSFCH transmission and/or reception basedon the priority value for the PSFCH or the PSFCH group.

For example, if the UE determines PSFCH transmission, the UE may selecta PSFCH to transmit by determining that a group having the lowestpriority value has a high priority among the PSFCH transmission groupfor SL HARQ-ACK feedback and the PSFCH transmission group correspondingto additional information. For example, if the UE determines PSFCHtransmission, the UE may select a PSFCH to transmit, among PSFCHtransmissions within the PSFCH transmission group for SL HARQ-ACKfeedback and the PSFCH transmission group corresponding to additionalinformation, by determining that the priority is higher as the priorityvalue is smaller.

In the embodiment, a PSFCH for an additional information request may bereplaced with or extended to PSFCH transmission and reception other thanSL HARQ-ACK feedback, such as a PSFCH for transmitting additionalinformation and/or a PSFCH for determining a UE for transmitting andreceiving additional information, etc.

For example, the UE-B may transmit an additional information request tothe UE-A in a specific situation. For example, the specific situationmay be a case in which the UE-B intends to perform transmission to theUE-A or a third UE which is UE-C, or a case in which the UE-B triggersresource (re)selection. For example, the specific situation may be afterthe UE-B determines a selected resource for PSCCH/PSSCH transmission.For example, the specific situation may be a case in which a ratio ofreceived NACKs and/or DTXs (or received ACKs) to all SL HARQ-ACKfeedback that the UE-B, which has transmitted TB(s) based on HARQ-ACKfeedback, expects to receive from the UE-A or the UE-C is greater thanor equal to a (pre-)configured threshold. For example, in the NACK orthe DTX, a portion corresponding to priority-based PSFCH skipping may beexcluded.

For example, the UE-B may determine a set of available resources of theUE-B based on additional information received from the UE-A.

For example, (Operation-1) if the UE-B does not detect first SCI in aspecific slot (e.g., due to transmission of the UE-B), the UE-B mayselect/configure/determine, as excluded resources within a resourceselection window, all frequency domain resources belonging to all orpart of slots (e.g., slots after resource reservation periods from thespecific slot) derived based on all or part of resource reservationperiod candidate values (e.g., resource reservation period candidatevalues greater than or equal to 100 msec or 20 msec among resourcereservation period candidate values) configured for a resource pool ofthe UE-B and the specific slot. In other words, for example, if (i)feasible reception pattern(s) determined based on resource reservationperiod candidate values from the specific slot and (ii) a transmissionpattern determined based on transmission resource reservation period(s),a transmission resource reselection counter, a transmission priority,and the number of transmission subchannels of the UE-B overlap, the UE-Bmay exclude the transmission pattern or a combination of a startingsubchannel and/or a slot of the transmission pattern from a set ofavailable resources.

For example, (Operation-2) if the UE-B does not detect first SCI in aspecific slot (e.g., due to transmission of the UE-B), the UE-B mayselect/configure/determine, as excluded resources within a resourceselection window, all frequency domain resources belonging to all orpart of slots (e.g., slots after resource reservation periods from thespecific slot) derived based on a specific resource reservation period(e.g., (pre-)configured resource reservation period(s) and transmissionresource reservation period(s) of the UE-B) and the specific slot. Inother words, for example, if (i) feasible reception pattern(s)determined based on the specific resource reservation period from thespecific slot and (ii) a transmission pattern determined based ontransmission resource reservation period(s), a transmission resourcereselection counter, a transmission priority, and the number oftransmission subchannels of the UE-B overlap, the UE-B may exclude thetransmission pattern or a combination of a starting subchannel and/or aslot of the transmission pattern from a set of available resources.

For example, (Operation-3) if the UE-B does not detect first SCI in aspecific slot (e.g., due to transmission of the UE-B), the UE-B may notselect, as excluded resources within a resource selection window, all(frequency domain) resources belonging to all or part of slots (e.g.,slots after resource reservation periods from the specific slot) derivedbased on all or part of resource reservation period candidate values(e.g., resource reservation period candidate values greater than orequal to 100 msec or 20 msec among resource reservation period candidatevalues) configured for a resource pool of the UE-B and the specificslot. That is, for example, the UE-B may select/configure/determine, asexcluded resources, only resources determined based on the additionalinformation among all (frequency domain) resources belonging to all orpart of slots (e.g., slots after resource reservation periods from thespecific slot). In other words, for example, the UE-B may determine areception pattern related to the specific slot based on resourceinformation indicated in additional information received by the UE-B inanother slot. In this case, for example, if the reception patternoverlaps with a transmission pattern determined based on transmissionresource reservation period(s), a transmission resource reselectioncounter, a transmission priority, and the number of transmissionsubchannels of the UE-B, and/or if an RSRP value corresponding to thereception pattern is greater than or equal to an RSRP threshold, theUE-B may exclude the transmission pattern or a combination of a startingsubchannel and/or a slot of the transmission pattern from a set ofavailable resources. For example, the RSRP value corresponding to thereception pattern may be indicated by additional information. Forexample, the additional information may include the RSRP valuecorresponding to the reception pattern. For example, the RSRP valuecorresponding to the reception pattern may be measured by the UE-B basedon signaling related to additional information. For example, the RSRPthreshold may be determined based on the transmission priority and apriority of the reception pattern.

For example, (Operation-4) if the UE-B does not detect first SCI in aspecific slot (e.g., due to transmission of the UE-B), the UE-B mayselect/configure/determine, as excluded resources, resources determinedbased on the additional information and all (frequency domain) resourcesbelonging to all or part of slots (e.g., slots after resourcereservation periods from the specific slot) derived based on a specificresource reservation period candidate values (e.g., (pre-)configuredresource reservation period(s) and transmission resource reservationperiod(s) of the UE-B) and the specific slot. In other words, forexample, the UE-B may determine a reception pattern for the specificslot based on (i) all (frequency domain) resources in slot(s) derivedbased on the specific resource reservation period and (ii) resourceinformation indicated in additional information received by the UE-B inanother slot. In this case, for example, if the reception patternoverlaps with a transmission pattern determined based on transmissionresource reservation period(s), a transmission resource reselectioncounter, a transmission priority, and the number of transmissionsubchannels of the UE-B, and/or if an RSRP value corresponding to thereception pattern is greater than or equal to an RSRP threshold, theUE-B may exclude the transmission pattern or a combination of a startingsubchannel and/or a slot of the transmission pattern from a set ofavailable resources. For example, the RSRP value corresponding to thereception pattern may be indicated by additional information. Forexample, the additional information may include the RSRP valuecorresponding to the reception pattern. For example, the RSRP valuecorresponding to the reception pattern may be measured by the UE-B basedon signaling related to additional information. For example, the RSRPthreshold may be determined based on the transmission priority and apriority of the reception pattern. For example, in the above case, theremay be no RSRP corresponding to a specific reception pattern. In thiscase, the UE-B may exclude a transmission pattern overlapping thespecific reception pattern from a set of available resources regardlessof the RSRP value.

For example, (Operation-5) if the UE-B does not detect first SCI in aspecific slot (e.g., due to transmission of the UE-B), the UE-B mayselect/configure/determine, as excluded resources, resources determinedbased on the additional information and all (frequency domain) resourcesbelonging to all or part of slots (e.g., slots after resourcereservation periods from the specific slot) derived based on resourcereservation period candidate values configured for a resource pool ofthe UE-B (e.g., resource reservation period candidate value(s) which isonly 20 msec or more or 100 msec or more) and the specific slot. In thiscase, for example, among slots derived based on the resource reservationperiod candidate values, a slot to which a resource indicated inadditional information belongs may be excluded. That is, for example,the UE-B may determine available resources for a slot indicated byadditional information based on a frequency domain resource indicated inthe additional information, and the UE-B may determine availableresources for the remaining slots corresponding to the specific slotbased on all frequency domain resources. In other words, for example, inorder to determine available resources, the UE-B may determine areception pattern corresponding to the specific slot, based on all orpart of slots (e.g., slots after resource reservation periods from thespecific slot) derived based on resource reservation period candidatevalues configured for a resource pool of the UE-B (e.g., only candidatevalues greater than or equal to 20 msec or greater than or equal to 100msec), and the UE-B may determine a frequency domain reception patternin the slot based on additional information, for slots corresponding toresources indicated by additional information among the slots, and theUE-B may determine a reception pattern such that all frequency domainresources are included for the remaining slots. In this case, forexample, if the reception pattern overlaps with a transmission patterndetermined based on transmission resource reservation period(s), atransmission resource reselection counter, a transmission priority, andthe number of transmission subchannels of the UE-B, and/or if an RSRPvalue corresponding to the reception pattern is greater than or equal toan RSRP threshold, the UE-B may exclude the transmission pattern or acombination of a starting subchannel and/or a slot of the transmissionpattern from a set of available resources. For example, the RSRP valuecorresponding to the reception pattern may be indicated by additionalinformation. For example, the additional information may include theRSRP value corresponding to the reception pattern. For example, the RSRPvalue corresponding to the reception pattern may be measured by the UE-Bbased on signaling related to additional information. For example, theRSRP threshold may be determined based on the transmission priority anda priority of the reception pattern. For example, in the above case,there may be no RSRP corresponding to a specific reception pattern. Inthis case, the UE-B may exclude a transmission pattern overlapping thespecific reception pattern from a set of available resources regardlessof the RSRP value.

For example, which of the above operations is to be performed by theUE-B may be (pre-)configured for each resource pool for the UE-B. Forexample, the base station/network may transmit information related to anoperation to be performed by the UE-B to the UE-B.

For example, UE-B may select (Operation-1), (Operation-2),(Operation-3), (Operation-4), (Operation-5) or a combination of theoperations, based on a priority value corresponding to resourcesindicated by additional information, a congestion control level,periodicity or aperiodicity, reception quality of additionalinformation, and/or whether the UE-B receives first SCI at the nextresource location of the corresponding resource. For example, if apriority value for the corresponding resource is less than or equal to aspecific threshold, the UE-B may select (Operation-1). For example, if apriority value for the corresponding resource is greater than or equalto a specific threshold, the UE-B may select (Operation-2),(Operation-3) or (Operation-4). In this case, for example, the thresholdmay be (pre-)configured to the UE for each resource pool. For example,the threshold may be (pre-)configured to the UE for each congestioncontrol level. For example, the threshold may be (pre-)configured to theUE for each QoS parameter. For example, if a received RSRP value foradditional information is greater than or equal to a (pre-)configuredthreshold, the UE-B may select (Operation-2), (Operation-3) or(Operation-4). For example, if a CBR value is less than or equal to a(pre-)configured threshold, the UE-B may select (Operation-2),(Operation-3) or (Operation-4). For example, if a received RSRP valuefor additional information is less than or equal to a (pre-)configuredthreshold, the UE-B may select (Operation-1). For example, if a CBRvalue is greater than or equal to a (pre-)configured threshold, the UE-Bmay select (Operation-1). For example, the operation methodselected/performed by the UE-B may be different based on a ratio ofavailable resources to resources within a resource selection window. Forexample, when the UE-B determines available resources based on(Operation-1), if the ratio of available resources cannot exceed a(pre-)configured threshold, the UE-B may perform (Operation-2),(Operation-3) or (Operation-4).

For example, the UE-B may re-evaluate selected resources reserved forPSCCH/PSSCH transmission of the UE-B based on additional informationreceived from the UE-A. For example, the additional information may be aset of preferred resources for PSCCH/PSSCH transmission of the UE-B. Inthis case, if all or part of reserved resources which the UE-B hasalready selected in a resource (re)selection procedure do not belong tothe set of preferred resources indicated by the additional information,the UE-B may report re-evaluation, pre-emption, or a third state for theresources to a higher layer (e.g., MAC layer). For example, theadditional information may be a set of non-preferred resources forPSCCH/PSSCH transmission of the UE-B. In this case, if all or part ofreserved resources which the UE-B has already selected in a resource(re)selection procedure overlap with the non-preferred resourcesindicated by the additional information, the UE-B may reportre-evaluation, pre-emption, or a third state for the resources to ahigher layer (e.g., MAC layer).

For example, before the UE-B transmits the resource reservationinformation through SCI or the like, the UE-B may report, to a higherlayer, re-evaluation, pre-emption, or a third state for reservedresources that do not match additional information. For example, if theUE-B has already transmitted the resource reservation informationthrough SCI or the like and/or if a pre-emption priority value is(pre-)configured for the UE and/or if a transmission priority value forreserved resources of the UE-B is greater than or equal to thepre-emption priority value and/or if a priority value for additionalinformation or a set of preferred resources indicated by additionalinformation is less than the pre-emption priority value and/or if apriority value for additional information or a set of preferredresources indicated by additional information is less than thetransmission priority value for reserved resources of the UE-B, the UE-Bmay report, to a higher layer, pre-emption, or a third state forreserved resources that do not match additional information.

For example, if the UE-B has already transmitted the resourcereservation information through SCI and/or if a pre-emption priorityvalue is (pre-)configured for the UE and/or if a transmission priorityvalue for reserved resources of the UE-B is greater than or equal to thepre-emption priority value and/or if a priority value for additionalinformation or a set of non-preferred resources indicated by additionalinformation is less than the pre-emption priority value and/or if apriority value for additional information or a set of non-preferredresources indicated by additional information is less than thetransmission priority value for reserved resources of the UE-B, the UE-Bmay report, to a higher layer, pre-emption, or a third state forreserved resources that do not match additional information.

Based on an embodiment of the present disclosure, the UE-A may transmit,to the UE-B, information related to time domain resource(s) throughwhich the UE-A cannot perform SL reception and/or information related totime domain resource(s) through which the UE-A can perform SL reception.For example, the UE-A may transmit, to the UE-B, information related tofrequency domain resource(s) through which the UE-A cannot perform SLreception and/or information related to frequency domain resource(s)through which the UE-A can perform SL reception. For example, theassistance information may include information related to time domainresource(s) through which the UE-A cannot perform SL reception and/orinformation related to time domain resource(s) through which the UE-Acan perform SL reception. For example, the assistance information mayinclude information related to frequency domain resource(s) throughwhich the UE-A cannot perform SL reception and/or information related tofrequency domain resource(s) through which the UE-A can perform SLreception. For example, the UE-A may transmit, to the UE-B, informationrelated to time domain resource(s) and/or information related tofrequency domain resource(s) in which the UE-A may have low receptionperformance. For example, the UE-A may transmit, to the UE-B,information related to time domain resource(s) and/or informationrelated to frequency domain resource(s) in which the UE-A may have highreception performance. For example, the low reception performance mayrefer to that a target error probability is greater than or equal to aspecific threshold. For example, the high reception performance mayrefer to that a target error probability is less than or equal to aspecific threshold. For example, the low reception performance may referto that a target SINR and/or a target SNR is less than or equal to aspecific threshold. For example, the high reception performance mayrefer to that a target SINR and/or a target SNR is greater than or equalto a specific threshold. For example, the low reception performance mayrefer to that a target interference level is greater than or equal to aspecific threshold. For example, the high reception performance mayrefer to that a target interference level is less than or equal to aspecific threshold. That is, if the UE-A intends to receive PSCCH/PSSCHfrom the UE-B, the UE-A may transmit information related to preferredresource(s) and/or information related to non-preferred resource(s) tothe UE-B. In this case, the UE-B may transmit PSCCH/PSSCH to a UE groupincluding at least UE-A by using resource(s) other than thenon-preferred resource(s). For example, the UE-B may transmitPSCCH/PSSCH to a UE group including at least UE-A by preferentiallyusing the preferred resource(s). For example, the UE-A maydetermine/configure a domain in which reception is not possible and/or adomain in which reception is possible, based on time when SLtransmission is scheduled and/or time when UL transmission is scheduledand/or time when DL reception is scheduled. For example, the ULtransmission and/or the DL reception may be limited totransmission/reception satisfying a specific condition (e.g., URLLC(e.g., corresponding to priority index 1)). For example, the ULtransmission and/or the DL reception may be limited totransmission/reception corresponding to system information and/or pagingand/or random access (e.g., PRACH and/or MsgA and/or Msg3 and/or randomaccess response and/or MsgB). For example, the UL transmission or the DLreception may be periodic transmission or reception. For example, the DLreception may be information regarding a slot and/or a symbol throughwhich the UE-A receives an SPS PDSCH. For example, the UL transmissionmay be information regarding a slot and/or a symbol through which theUE-A reports periodic CSI or SPS CSI. For example, the UL transmissionmay be information regarding a PUSCH resource corresponding to aconfigured grant (CG) of the UE-A. For example, when the UE-A actuallyuses the PUSCH resource corresponding to the CG, corresponding resourceinformation may be included in assistance information. For example,information related to a time domain resource in which the UE-A cannotreceive SL may be information regarding a time period in which the UE-Aperforms LTE SL communication. For example, the information regardingthe time period for performing the LTE SL communication may beinformation regarding NR slots and/or symbols overlapping the timeperiod for transmitting or receiving an LTE SL synchronization signaland/or a PSBCH and/or a semi-periodic PSCCH/PSSCH. For example, in thecase of the periodic PSCCH/PSSCH transmission/reception, the UE-A mayknow a resource reservation period. This is because in the case of LTEV2X, the PSCCH/PSSCH may also be transmitted periodically inconsideration of periodic traffic. For example, regarding the time whenperiodic transmission and reception of the PSCCH/PSSCH ends orthereafter, the UE-A may still consider the corresponding resources asreserved resources and determine that NR SL reception is impossibleduring the time period. Or, for example, regarding the time whenperiodic transmission and reception of the PSCCH/PSSCH ends orthereafter, the UE-A may determine to exclude corresponding resourcesfrom the time period in which NR SL reception is impossible. Forexample, from the point of view of the UE-A, the time when NR SLtransmission is scheduled may be resource information regarding selectedresources of the UE-A. Meanwhile, NR SL transmission of the UE-A may betransmitted in a different resource (due to resource reselection of theUE-A) due to LTE SL transmission and reception and/or UL transmission ofthe UE-A. Meanwhile, based on congestion control, the UE-A may changeall or part of selected resources for SL transmission. For example,information regarding the time when NR SL transmission is scheduled mayinclude resources newly added by resource re-evaluation and/orpre-emption of the UE-A. For example, information regarding a resourcewhich has been canceled due to resource re-evaluation and/or pre-emptionof the UE-A may be excluded from information regarding the time when NRSL transmission is scheduled. For example, information regarding thetime when NR SL transmission is scheduled may still include informationregarding a resource which has been canceled due to resourcere-evaluation and/or pre-emption of the UE-A.

In this case, for example, the location of the periodic resources may beindicated by the form of a period and/or a physical slot offset valuefor a physical slot. For example, the location of the periodic resourcesmay be limitedly indicated for cell-specific UL slots or slots includingUL resources. In this case, for example, the slot including the ULresource may be a slot in which a symbol period corresponding to thenumber of SL symbols from an SL start symbol is the UL resource. Forexample, the location of the periodic resources may be limitedlyindicated for slots in which SL communication is possible. In this case,for example, S-SSB slots may be excluded from the slots in which SLcommunication is possible. For example, the location of the periodicresources may be limitedly indicated for slots in a resource pool.

For example, the UE-A may determine/configure a corresponding resource,based on whether an RSRP measurement value for each resource (e.g.,slot, subchannel, group of slots and/or group of subchannels) is higherthan or lower than a specific threshold through a sensing operation. Forexample, the specific threshold may be (pre-)configured, pre-defined, orselected by UE implementation. For example, the UE-A maydetermine/configure a corresponding resource, based on an SINRestimation value and/or an RS SI measurement value for each resource(e.g., slot, subchannel, group of slots, and/or group of subchannels).

For example, when the UE-A transmits additional information to the UE-B,the UE-A may indicate preferred resources and/or non-preferred resourcesfor transmission of the UE-B, based on a sensing result of the UE-Aand/or other additional information received by the UE-A and/orinformation regarding a time when the UE-A cannot receive SL reception.Meanwhile, the UE-A may not be able to express all preferred resourcesand/or all non-preferred resources due to the limitation of the payloadsize of additional information. In addition, meanwhile, whentransmitting in the form of non-contiguous resources for preferredresources, the required payload size may become too large. For example,the UE-A may simultaneously transmit a preferred resource and anon-preferred resource. For example, the preferred resource may indicatecontinuous time resources and/or frequency resources. For example, thenon-preferred resource may indicate discontinuous time resources and/orfrequency resources within the preferred resource. For example, uponreceiving the additional information from the UE-A, the UE-B may selectan available resource by prioritizing a resource in the preferredresource, while the UE-B may exclude the non-preferred resource. Forexample, upon receiving the additional information from the UE-A, theUE-B may select an available resource by prioritizing a resource in thepreferred resource, and the UE-B may lower the priority such that thenon-preferred resource is excluded.

Meanwhile, PSFCH transmission and PSFCH reception of the UE-A mayoverlap in the same slot. In this case, the UE-A may skip one of PSFCHtransmission or PSFCH reception. Due to the skipping operation, the UEwhich needs to receive the corresponding PSFCH may process thecorresponding SL HARQ-ACK feedback information as NACK (in unicast orthe groupcast HARQ-ACK feedback option 2). In this case, ACK may betreated as NACK, which may increase retransmission resources. Or, due tothe skipping operation, the UE which needs to receive the correspondingPSFCH may process the corresponding SL HARQ-ACK feedback information asACK (in the groupcast HARQ-ACK feedback option 1). In this case, NACKmay be treated as ACK, which may increase the latency time. For example,the UE-A may include information regarding all or part of slots in whichthe UE-A performs PSFCH transmission in additional information. Forexample, the slot may be a slot belonging to a reference time period(e.g., the reference time period is (pre-)configured or indicatedthrough additional information). For example, the UE-A may includeinformation on how many PSFCH transmissions are scheduled or expectedfor PSFCH transmission slots in additional information. In this case,for example, the UE-B which has received the additional information maytransmit a PSCCH/PSSCH to the UE-A by avoiding PSSCH resourcesassociated with PSFCH slots indicated by the additional information. Forexample, if the UE-B determines that the UE-A can further transmit aPSFCH in a PSFCH slot indicated by the additional information, the UE-Bmay transmit a PSCCH/PSSCH to the UE-A in a slot associated with thecorresponding PSFCH slot. For example, the UE-A may include informationregarding all or part of slots in which the UE-A performs PSFCHreception in additional information. For example, the slot may be a slotbelonging to a reference time period (e.g., the reference time period is(pre-)configured or indicated through additional information). In thiscase, for example, the UE-B which has received the additionalinformation may transmit a PSCCH/PSSCH to the UE-A by avoiding PSSCHresources associated with PSFCH slots indicated by the additionalinformation.

For example, the UE-A may determine preferred resource information ornon-preferred resource information for the UE-B transmitted throughadditional information, based on whether there is a power limited casein a PSFCH TX slot and/or the number of PSFCH transmissions in a PSFCHTX slot and/or the location of a PSFCH RX slot and/or the location of aPSFCH TX slot of the UE-A. For example, the UE-A may configure a PSSCHslot associated with a PSFCH TX slot or a PSFCH RX slot of the UE-A as anon-preferred resource. For example, in the case of a PSSCH slotassociated with a PSFCH TX slot, if additional PSFCH TX of the UE-A isavailable and/or if it is not a power limited case (before or afterapplying additional PSFCH transmission), the PSSCH slot associated withthe PSFCH TX slot may be excluded from the non-preferred resource. Forexample, the UE-A may configure all or part of PSSCH slots notassociated with a PSFCH TX slot or a PSFCH RX slot of the UE-A as apreferred resource. For example, in the case of a PSSCH slot associatedwith a PSFCH TX slot, if additional PSFCH TX of the UE-A is availableand/or if it is not a power limited case (before or after applyingadditional PSFCH transmission), the PSSCH slot associated with the PSFCHTX slot may be included in the preferred resource. Meanwhile, the UE-Bmay differently set SL HARQ-ACK feedback enable/disable for each periodfor periodic reservation resources, and the UE-B may perform PSCCH/PSSCHtransmission based on the periodic reservation resources. In the abovecase, even if the UE-A observes a PSFCH TX/TX and/or TX/RX conflictbased on received SCI of the previous period, if the UE-B disables SLHARQ-ACK feedback in the next period, the PSFCH conflict may no longeroccur. For example, the UE-A may refer to/use a PSFCH TX/TX and/or TX/RXconflict predicted in a specific reservation period of the UE-B onlywhen generating assistance information for reserved resources of theUE-B for the same TB. For example, the UE-A may refer to/use a PSFCHTX/TX and/or TX/RX conflict predicted in a specific reservation periodof the UE-B when generating assistance information for another TB oranother reservation period, and the UE-A may transmit the assistanceinformation to the UE-B by including the consideration of the PSFCHconflict factor. In this case, for example, if the UE-B enables SLHARQ-ACK feedback in the next reservation period, the UE-B may use theassistance information for resource (re)selection. For example, if theUE-B disables SL HARQ-ACK feedback in the next reservation period, theUE-B may not use the assistance information for resource (re)selection.That is, for example, if the UE-B disables SL HARQ-ACK feedback in thenext reservation period, the UE-B may ignore the assistance informationwhen performing resource (re)selection.

For example, when the UE-A configures transmission preferred resourcesfor the UE-B through additional information, the additional informationmay include information regarding all or part of slots satisfying aspecific condition. For example, the information on the slot may beinformation within a reference time period. For example, the referencetime period may be (pre-)configured or indicated by additionalinformation. For example, the specific condition may be all or part ofslots excluding slots associated with PSFCH TX slots of the UE-A and/orslots associated with slots in which the UE-A performs PSFCH RX and/orselection/reservation resources of the UE-A and/or SL slots overlappingwith LTE SL resources (LTE SL synchronization signal, LTE PSBCH, LTE SPSPSCCH/PSSCH) and/or periodic DL resources and/or periodic ULtransmission resources of the UE-A (periodic/semi-periodic CSI report,CG PUSCH).

For example, the UE-A may transmit additional information to the UE-Bunder a specific condition. This case may include, for example, a casein which the UE-A determines to perform an NR SL reception operation.

For example, from the point of view of the UE-A, the specific conditionmay include a case in which the number of PSFCH slots in which PSFCHtransmission and PSFCH reception collide is greater than or equal to a(pre-)configured threshold. For example, the UE-A may increase aspecific timer when PSFCH transmission and PSFCH reception collide. Inaddition, if the timer reaches a (pre-)configured value, the UE-A maytransmit additional information. For example, the timer may be(re)started when a conflict between PSFCH transmission and PSFCHreception does not occur in a PSFCH slot. For example, the timer may be(re)started when the UE-A transmits additional information.

For example, from the point of view of the UE-A, the specific conditionmay include a case in which the number of PSFCH slots in which thenumber of simultaneous transmissions of PSFCH transmission is greaterthan or equal to a first threshold is greater than or equal to a(pre-)configured second threshold. For example, the first threshold maybe a (pre-)configured value. For example, the first threshold may be themaximum number of PSFCHs that can be simultaneously transmitted by theUE-A. For example, the UE-A may increase a specific timer when thenumber of simultaneous PSFCH transmissions is greater than or equal tothe first threshold. For example, the UE-A may increase a specific timerwhen power scaling is performed for a PSFCH due to simultaneous PSFCHtransmission. For example, if the timer reaches a (pre-)configuredvalue, the UE-A may transmit additional information. For example, if thenumber of simultaneous PSFCH transmissions is less than or equal to thefirst threshold and/or if power scaling is not performed for a PSFCH,the timer may be (re)started. For example, the timer may be (re)startedwhen the UE-A transmits additional information.

For example, from the point of view of the UE-A, the specific conditionmay include a case in which the number of times that NR SL reception islimited due to LTE SL transmission and reception is greater than orequal to a (pre-)configured threshold. For example, the LTE SLtransmission and reception may be limited to an LTE SL synchronizationsignal, an LTE PSBCH, and/or an SPS PSCCH/PSSCH. Even in the case ofthis condition, it may be expressed in the form of a timer.

For example, from the point of view of the UE-A, the specific conditionmay include a case in which the number of times NR SL reception islimited due to NR UL transmission and/or NR DL reception is greater thanor equal to a (pre-)configured threshold. For example, the NR UL/DLtransmission/reception may be limited to periodic resources (e.g.,periodic/SPS CSI report, CG PUSCH, SPS PDSCH). Even in the case of thiscondition, it may be expressed in the form of a timer.

For example, if an RSRP measurement value measured by the UE-A based onan RS received from the UE-B is greater than or equal to and/or exceedsa (pre-)configured threshold, the UE-A may trigger transmission ofadditional information. In this case, for example, only if the number oftimes the RSRP measurement value is greater than or equal to and/orexceeds a specific threshold is greater than or equal to a(pre-)configured threshold, transmission of additional information maybe triggered. For example, if an RSRP measurement value measured by theUE-A based on an RS received from the UE-B is greater than or equal toand/or exceeds a (pre-)configured threshold, the UE-A may increase ordecrease a specific timer. In this case, if the corresponding timerexpires or if it is reached to the (pre-)configured maximum value, theUE-A may trigger transmission of additional information. For example,the RS used for the RSRP measurement may be a PSSCH DMRS transmitted bythe UE-B. For example, the RS used for the RSRP measurement may be aPSCCH DMRS transmitted by the UE-B. For example, the RS used for theRSRP measurement may be (pre-)configured. For example, if the UE-A failsto decode the PSCCH/PSSCH transmitted by the UE-B, the UE-A may triggertransmission of additional information. In this case, for example, onlyif the number of cases in which the number of failed decoding of thePSCCH/PSSCH is greater than or equal to and/or exceeds a specificthreshold is greater than or equal to a (pre-)configured threshold,transmission of additional information may be triggered. For example,only if the number of cases in which a ratio of PSCCH/PSSCH decodingfailures to all PSCCHs/PSSCHs transmitted by the UE-B is greater than orequal to and/or exceeds a specific threshold is greater than or equal toa (pre-)configured threshold, transmission of additional information maybe triggered. For example, if the UE-A fails to decode a PSCCH/PSSCHtransmitted by the UE-B, the UE-A may increase or decrease a specifictimer. In this case, if the corresponding timer expires or if it isreached to the (pre-)configured maximum value, the UE-A may triggertransmission of additional information.

For example, if the condition is checked based on a timer, each conflictrelated timer may be managed/exist differently for each condition. Forexample, if at least one timer related to a specific condition expires,the UE-A may transmit additional information. For example, if thecondition is checked based on a timer, each conflict related timer maybe managed/existed in common regardless of conditions. For example, theUE-A may increase the common conflict timer if at least one specificcondition occurs.

Based on an embodiment of the present disclosure, the UE-A may triggerand/or suggest resource reselection to the UE-B for all or part ofselected resources of the UE-B. For example, the UE-A may observe that aresource conflict occurs between all or part of resources of the UE-Band resources of a third UE (e.g., UE-C). However, in this case, theUE-B may not be aware of the resource conflict situation. In this case,for example, the UE-A may instruct the UE-B and/or the UE-C to reselectall or part of resources.

For example, if the UE-A observes that reserved resources/selectionresources indicated by received different SCI and/or additionalinformation overlap each other, or if the above situation occurs above acertain level, the UE-A may transmit additional information to the UE-B.For example, if the number of slots in which the UE-A observes that aspecific resource is indicated by different SCI and/or additionalinformation is greater than or equal to a (pre-)configured threshold,the UE-A may transmit additional information. For example, theadditional information may indicate time and/or frequency domainresources in which the UE-A observed a conflict. In this case, forexample, if all or part of selected resources of the UE-B overlap, theUE-B which has received the additional information may perform resourcereselection for all or part of selected resources of the UE-B orselected resources overlapping the indicated resources. For example, ifthe number of selected resources of the UE-B overlapping with resourcesindicated by additional information is greater than or equal to a(pre-)configured threshold, the UE-B may perform resource reselectionbased on the additional information. For example, if a ratio of thenumber of selected resources of the UE-B overlapping with resourcesindicated by additional information to the total number of selectedresources of the UE-B is greater than or equal to a (pre-)configuredthreshold, the UE-B may perform resource reselection based on theadditional information.

For example, the UE-A may relay all or part of SCI received by the UE-Ato the UE-B. For example, if the UE-A receives first SCI from the UE-Band the UE-C, respectively, and if all or part of resources indicated byeach SCI overlap, the UE-A may generate SCI (e.g., first SCI and/orsecond SCI) indicating all or part of an L1 source ID, an L1 destinationID, and/or reserved resources of the UE-C, and the UE-A may transmit thegenerated SCI to the UE-B. In this case, for example, the UE-B mayassume/determine that SCI transmitted by the UE-A is SCI transmitted bythe UE-C. In this case, for example, even though the UE-B does notrecognize the UE-C, the UE-B may be aware of reserved resources of theUE-C. For example, the UE-B may perform RSRP measurement for reservationinformation of the UE-C transmitted by the UE-A, based on thecorresponding PSSCH DMRS transmitted by the UE-A. In addition, if thecorresponding RSRP measurement value is greater than or equal to aspecific RSRP threshold, the UE-B may exclude the corresponding resource(a resource set overlapping with the corresponding resource) fromavailable resources of the UE-B. For example, the RSRP threshold may bea (pre-)configured for each combination of a TX priority and an RXpriority. For example, the TX priority may be obtained from packetinformation of the UE-B, and the RX priority may be a TX priority of theUE-C transmitted by the UE-A through SCI. Meanwhile, the UE-B hasalready received SCI transmitted by the UE-C, but the UE-B may determinethat the interference is low due to an RSRP measurement value-basedsensing operation, so the UE-B may include reserved resources of theUE-C in available resources of the UE-B. In this case, it may beunnecessary for the UE-A to operate like the UE-C as described above.For example, if the UE-B receives a plurality of SCI indicating the samepriority value, the same L1 source ID, and/or the same L1 destination IDfor the same resource, the UE-B may determine that only specific SCI isvalid, and the UE-B may perform resource (re)selection based on thecorresponding SCI. For example, the SCI selected as valid may be SCIhaving a high RSRP measurement value corresponding to the correspondingSCI. For example, SCI selected as valid may be SCI having a low RSRPmeasurement value corresponding to the corresponding SCI. For example,SCI selected as valid may be SCI that is not marked as additionalinformation or relay information (in a field (combination) form ortransmission form). For example, the UE-B may transmit an L1 source IDand/or an L1 destination ID for received SCI to the UE-A, and based onthis, the UE-A may relay only SCI of UE(s) not detected by the UE-B. Forexample, a PSFCH resource may be (additionally) allocated for each PSSCHresource (e.g., a combination of a starting subchannel and a slot of aPSSCH or a combination of allocated subchannels and a slot of a PSSCH).In this case, for example, for each PSSCH resource, a PSFCH resource forSL HARQ-ACK feedback for the corresponding PSSCH and a PSFCH resourcefor feedback regarding whether a conflict situation occurs orreselection is required for the corresponding PSSCH resource may be(pre-)configured to the UE. For example, each of PSFCH resources maycorrespond to different PRB sets. For example, a set of PSFCH resourcesfor SL HARQ-ACK feedback and a set of PSFCH resources for resourcereselection feedback may be (pre-)configured to the UE, and/or each setof PSFCH resources may have the same PSFCH resource period and the samePSFCH occasion. For example, each set of PSFCH resources may havedifferent PRB sets. For example, when mapping between a PSSCH resourceand a PSFCH resource, whether the mapping is based on a startingsubchannel for a PSSCH or allocated subchannels for a PSSCH may beconfigured differently for each set of PSFCH resources.

For example, if all or part of resources of the UE-B and the UE-Ccollide, the UE-A may indicate whether or not there is a resourceconflict by using a PSFCH resource corresponding to a PSSCH resource ofthe UE-B and/or the UE-C of the corresponding slot. For example, if aresource conflict does not occur, the UE-A may not perform PSFCHtransmission (for feedback regarding whether a resource conflictsituation occurs or resource reselection is required) corresponding to aPSSCH resource. For example, only if the PSSCH resource conflictsituation occurs in the HARQ-ACK feedback option 1 in groupcast, the UEmay transmit feedback regarding the resource conflict situation. This isbecause, in case of unicast or the HARQ-ACK feedback option 2 ingroupcast, when the receiving UE cannot transmit SL HARQ-ACK feedbackdue to a resource conflict, the transmitting UE may treat it as NACK andperform retransmission for the corresponding TB again. On the otherhand, this is because when the receiving UE does not transmit a PSFCHdue to a resource conflict in the groupcast HARQ-ACK feedback option 1,the transmitting UE may mistakenly determine this as ACK.

For example, if all or part of reserved resources indicated by SCItransmitted by the UE-B and the UE-C collide, the UE-A may indicatewhether or not there is a resource conflict by using a PSFCH resourcecorresponding to a PSSCH resource of the UE-B and/or the UE-C of thecorresponding slot. For example, a PSSCH resource at a time when SCI istransmitted may be excluded from the reserved resources. For example, aPSSCH resources at a time when SCI is transmitted may be included in thereserved resources. For example, when the UE-A instructs the UE-B and/orthe UE-C whether or not there is a resource conflict, the UE-A canidentify a resource in which a conflict occurs or reselection isrequired, and based on this, the UE-A may perform transmission byselecting different PSFCH resources. For example, if a conflict occursin the first reserved resource of the UE-B or the UE-C or if reselectionis required, the UE-A may transmit ACK based on a PSFCH resource. Forexample, if a conflict occurs in the second reserved resource of theUE-B or the UE-C or if reselection is required, the UE-A may transmitNACK based on a PSFCH resource. For example, if a resource conflict(including a half-duplex problem) occurs in a slot in which SCI isreceived, the UE-A may transmit NACK based on a PSFCH resourcecorresponding to a PSSCH transmitted by the UE-B and/or the UE-C. Forexample, if the UE-A determines that a resource conflict (including ahalf-duplex problem) occurs in reserved slot(s) indicated by SCI, theUE-A may transmit ACK based on a PSFCH resource corresponding to a PSSCHtransmitted by the UE-B and/or the UE-C. For example, the PSFCH resourcemay be a PSFCH resource corresponding to SL HARQ-ACK transmission. Inthis case, in the case of the groupcast HARQ-ACK feedback option 1, aPSFCH resource corresponding to ACK that has not been previously usedmay be used for transmission of additional information. For example,based on a PSFCH resource (e.g., m0 value) and/or based on an indicationvalue of a PSFCH resource (e.g., mcs value), resources (resource sets)reselected by the UE which has received additional information may bedifferent. For example, resource reselection by the UE which hasreceived additional information may be different based on PSFCHresources and/or indication values. For example, if a resource conflictoccurs in a resource already transmitted through additional information,retransmission may be performed in an already reserved resource withoutresource reselection for a later resource. For example, if a resourceconflict occurs in a resource reserved later through additionalinformation, resource reselection may be performed for the laterresource. For example, if a resource conflict occurs in a resourcereserved for later retransmission in the additional information, the UEmay perform resource reselection for the retransmission resource only ifa resource conflict occurs in an already transmitted resource for thesame TB or only if the UE determines NACK for the previously transmittedPSSCH. For example, if a resource conflict does not occur betweenreserved resources, PSFCH transmission (for feedback regarding whether aresource conflict situation occurs or resource reselection is required)corresponding to a PSSCH resource may not be performed.

For example, if the UE-A determines that the UE-B and the UE-C performtransmission and reception each other in the same slot, the UE-A mayindicate whether to perform resource reselection by using a PSFCHresource corresponding to a PSSCH resource of the UE-B and/or the UE-Cof the corresponding slot. In this case, for example, the case in whichit is determined that transmission and reception are performed in thesame slot may be a case in which the UE-B and the UE-C are in unicastcommunication and/or an L1 source ID and an L1 destination ID of theUE-B and the UE-C are set to an L1 destination ID and an L1 source IDwith each other. For example, the UE may indicate through a PSFCHresource (e.g., m0 value) and/or a PSFCH indication value (e.g., mcs),by distinguishing that a resource conflict occurs or a transmission andreception problem with each other occurs due to the half-duplex problem.

For example, if the receiving UE receives SCI from the transmitting UE,the receiving UE may obtain reserved resource information indicated bythe corresponding SCI. In this case, the receiving UE may not be able toperform SL reception at the transmission time on the reserved resourcedue to the half-duplex operation in a part of reserved resources. Inthis case, for example, the receiving UE may transmit NACK or ACK forthe reserved resource based on the reserved resource information eventhough SCI is not detected due to the half-duplex operation. Forexample, the above operation may be limited to a case in which thereceiving UE performs the groupcast HARQ-ACK feedback option 1. This isbecause when the receiving UE does not transmit a PSFCH due tonon-detection of SCI, the transmitting UE may mistake it for ACK. If thereceiving UE transmits NACK even though it does not detect SCI, thisproblem can be alleviated.

For example, in the case of the groupcast HARQ-ACK feedback option 1, ifthe UE-A fails to decode a PSSCH transmitted by the UE-B, the UE-A maytransmit NACK by using a PSFCH resource corresponding to the PSSCH. Forexample, if the UE-A successfully decodes the PSSCH, and if the UE-Adetermines a resource conflict (including half-duplex problem) for allor part of PSSCH resources, the UE-A may transmit additional informationfor the PSSCH to the UE-B.

For example, regardless of whether the transmitting UE enables ordisables SL HARQ-ACK feedback, the UE may perform PSFCH transmission forthe resource reselection indication according to the specific situation.For example, only if SL HARQ-ACK feedback of the transmitting UE isenabled, the UE may perform PSFCH transmission for the resourcereselection indication.

Meanwhile, the UE-B may receive additional information from a pluralityof UEs. In this case, a method for utilizing this needs to be defined.For example, the UE-B may utilize only additional informationtransmitted by a specific UE. For example, if the UE-B receivesadditional information from a plurality of UE-As, the UE-B may measureRSRP based on signals transmitted by the plurality of UE-As, and thespecific UE may be a UE corresponding to the largest RSRP measurementvalue. For example, the specific UE may be a UE having the closestgeographical distance to the UE-B. For example, the specific UE may be aUE that has completed a PC5-RRC connection with the UE-B.

For example, the UE-B which has received additional information may usethe additional information before the UE-B triggers a resource(re)selection operation. For example, the UE-B may skip a sensingoperation (e.g., attempting to detect SCI) in all or part of slots basedon information indicated by additional information. For example, if thetype of information indicated by additional information is anon-preferred resource for transmission of the UE-B, the UE-B may skip asensing operation for all or part of slots corresponding to thenon-preferred resource. For example, if the type of informationindicated by additional information is a preferred resource fortransmission of the UE-B, the UE-B may perform a sensing operation onlyfor all or part of slots corresponding to the preferred resource. Theslots corresponding to the preferred resource or the non-preferredresource may be derived based on resource reservation period candidatevalues (for the UE-B) or (pre-)configured resource reservationperiod(s). For example, for slots before resource reservation period(s)from the preferred resource or the non-preferred resource or slotsbefore the multiple of the resource reservation period(s) from thepreferred resource or the non-preferred resource, the UE-B may determinewhether to perform sensing. For example, the UE-B which has receivedadditional information may stop a sensing operation. For example, thestop condition may be limited to a case in which additional informationindicates a resource within a resource selection window of the UE-B. Forexample, the stop condition may be limited to a case in which additionalinformation is information corresponding to the number of transmissionsubchannels and/or a transmission resource reservation period and/or atransmission priority of the UE-B. For example, if a ratio of the amountof available resources determined based on (preferred or non-preferred)resources indicated by additional information to the total amount ofresources within a resource selection window of the UE is less than orequal to a (pre-)configured threshold, the UE which has received theadditional information may skip a sensing operation (e.g., SCI detectionattempt and/or an available resource selection procedure).

For example, if the UE-B which has received additional information mayuse the additional information at a time when the UE-B triggers aresource (re)selection operation or after a specific time from the time.For example, the specific time may be pre-defined. For example, thespecific time may be (pre-)configured to the UE. For example, the UE-Bwhich has received additional information may exclude a transmissionpattern of the UE-B partially overlapping with a resource indicated bythe additional information from available resources. For example, thetransmission pattern may be determined based on the number oftransmission subchannels, a transmission resource reservation periodand/or a transmission priority of the UE-B. For example, the UE-B whichhas received additional information may configure all or part ofresources indicated by the additional information as available resourcesthat can be used to transmit a transmission pattern of the UE-B.Meanwhile, a reference resource selection window corresponding toadditional information may not include all resource selection windows ofthe UE-B. For example, within a resource selection window of the UE-Bother than the reference resource selection window corresponding to theadditional information, the UE-B may perform a resource selectionprocedure (e.g., available resource selection) based on received firstSCI.

For example, when the UE-B determines available resources within aresource selection window, the UE-B which has received additionalinformation may use the additional information together with receivedfirst SCI information. For example, the UE-B may select availableresources in consideration of a transmission pattern based on arepresentative RSRP measurement value corresponding to resourcesindicated by additional information. For example, the UE-B may determineavailable resources based on the received first SCI and thecorresponding RSRP measurement value, and the UE-B may again excludeavailable resources that overlaps with resources indicated by theadditional information from the determined available resources. Forexample, the UE-B may determine available resources based on thereceived first SCI and the corresponding RSRP measurement value, andthen the UE-B may again include resources overlapping with resourcesindicated by the additional information in the determined availableresources. Through this, the UE-B may expand available resources.Specifically, for example, if an RSRP measurement value corresponding toadditional information is less than or equal to and/or less than a(pre-)configured RSRP threshold, the UE-B may perform a procedure ofextending available resources based on the additional information. Forexample, the RSRP threshold may be (pre-)configured for eachtransmission priority, and the threshold to be used may be selectedbased on a transmission priority of the UE-B.

For example, when the UE-B determines a selected resource from availableresources, the UE-B which has received additional information may usethe additional information. For example, the UE-B may select theselected resource from resources indicated by the additional informationwithin available resources. For example, the additionalinformation-based selected resource selection procedure may be limitedto a case in which an RSRP measurement value corresponding to resourcesindicated by the additional information is less than or equal to and/orless than a (pre-)configured RSRP threshold. For example, the RSRPthreshold may be (pre-)configured for each transmission priority, andthe threshold to be used may be selected based on a transmissionpriority of the UE-B. For example, the UE-B may select a selectedresource other than resources indicated by the additional informationwithin available resources. For example, the additionalinformation-based selected resource selection procedure may be limitedto a case in which an RSRP measurement value corresponding to resourcesindicated by the additional information is greater than or equal toand/or greater than a (pre-)configured RSRP threshold. For example, theRSRP threshold may be (pre-)configured for each transmission priority,and the threshold to be used may be selected based on a transmissionpriority of the UE-B.

For example, after the UE-B determines a selected resource fromavailable resources, the UE-B which has received additional informationmay use the additional information. For example, if the selectedresource of the UE-B does not include all or part of resources indicatedby the additional information, the UE-B may perform resource reselectionfor all or part of non-overlapping selected resource. For example, ifthe overlapping ratio of the resource selected by the UE-B to resourcesindicated by the additional information is less than or equal to a(pre-) configured ratio, the UE-B may perform the above procedure. Forexample, if it is difficult to satisfy the above condition due toresource reselection, the UE-B may increase an RSRP threshold andperform the operation again from selecting available resources. Forexample, if the selected resource of the UE-B includes all or part ofresources indicated by the additional information, the UE-B may performresource reselection for all or part of overlapping selected resource.For example, if the selected resource of the UE-B includes even a partof resources indicated by the additional information, the UE-B mayperform resource reselection for all or part of overlapping selectedresource. For example, if the overlapping ratio of the resource selectedby the UE-B to resources indicated by the additional information isgreater than or equal to a (pre-)configured ratio, the UE-B may performthe above procedure. For example, if it is difficult to satisfy theabove condition due to resource reselection, the UE-B may increase anRSRP threshold and perform the operation again from selecting availableresources.

Meanwhile, after the UE-B receives additional information from the UE-A,the UE-B may receive new additional information from the UE-A or receiveadditional information from a third UE (e.g., UE-C). In the abovesituation, it is necessary to determine how the UE-B uses additionalinformation. For example, if the UE-B completes or is performingresource (re)selection, the UE-B may not use newly received additionalinformation until the next resource (re)selection is triggered. Forexample, if the UE-B completes or is performing resource (re)selection,the UE-B may not use newly received additional information until theUE-B completes current TB transmission. For example, if the UE-Breceives additional information from a new UE, and if an RSRPmeasurement value based on an SL channel transmitted by the new UE isgreater than an RSRP measurement value based on an SL channeltransmitted by the previous UE or if an RSRP measurement value based onan SL channel transmitted by the new UE is greater than an RSRPmeasurement value based on an SL channel transmitted by the previous UEby a certain level (e.g. pre-defined value or (pre-)configured value) ormore, the UE-B may use new additional information. For example, if theUE-B receives new additional information, the UE-B may trigger resource(re)selection. For example, triggering of resource (re)selection by theadditional information may be performed by the UE-B only in a specificsituation. For example, the specific situation may be a case in whichprevious additional information and new additional information receivedby the UE-B are different from each other. For example, the differentadditional information may be a case in which resources indicated bypreviously received additional information and resources indicated bynewly received additional information do not overlap each other or anon-overlapping ratio between resources indicated by previously receivedadditional information and resources indicated by newly receivedadditional information is greater than or equal to a certain level. Forexample, the specific situation may be a case in which a transmissionpriority value of the UE-B is greater than a priority value of aspecific resource indicated by additional information. For example, thespecific situation may be a case in which a transmission priority valueof the UE-B is greater than a priority value of additional information.For example, the specific situation may be a case in which a priorityvalue of a specific resource indicated by additional information is lessthan a (pre-)configured threshold. For example, the specific situationmay be a case in which a priority value of additional information isless than a (pre-)configured threshold. For example, the specificsituation may be a case in which the remaining PDB is sufficient even ifresource (re)selection is performed according to packet information ofthe UE-B. For example, the specific situation may be a case in which anRSRP value corresponding to a specific resource indicated by additionalinformation is greater than or equal to a (pre-)configured threshold.For example, the specific situation may be a case in which an RSRP valuefor additional information is greater than or equal to a(pre-)configured threshold. In this case, for example, the RSRPmeasurement value may be measured by the UE-B based on RS used totransmit additional information. For example, the specific situation maybe a case in which the reception quality of previously receivedadditional information by the UE-B is lower than the reception qualityof newly received additional information. In this case, for example, bycomparing RSRP measurement values for transmission of additionalinformation, an RSRP measurement value of newly received additionalinformation is greater than an RSRP measurement value of previouslyreceived additional information, or an RSRP measurement value of newlyreceived additional information is greater than an RSRP measurementvalue of previously received additional information by a(pre-)configured offset or more. For example, the specific situation maybe a case in which a priority value for newly received additionalinformation by the UE-B is less than a priority value for previouslyreceived additional information. For example, the specific situation maybe a case in which distance information for newly received additionalinformation by the UE-B is smaller than distance information forpreviously received additional information. In this case, for example,the distance between the UE transmitting the additional information andthe UE-B (e.g., distance measurement based on ZONE ID, etc.) mayrepresent the distance information. For example, the specific situationmay be a case in which resources indicated by additional information isinformation related to an SL reception unavailable domain of the UEtransmitting additional information.

For example, when the UE-B receives a set of preferred resources or aset of non-preferred resources through additional information from eachof a plurality of UEs, and the UE-B transmits a PSCCH/PSSCH to each ofthe plurality of UEs, the UE-B may preferentially use additionalinformation transmitted by the corresponding UE for resource(re)selection. For example, if the UE-B receives a set of non-preferredresources through additional information from each of a plurality ofUEs, the UE-B may first select available resources within a resourceselection window of the UE-B based on the set of non-preferredresources. In this case, for example, if a ratio of available resourcesis less than a specific threshold (e.g., a (pre-)configured parameter),the UE-B may no longer consider the set of non-preferred resourcesindicated by a part of additional information. For example, if the UE-Breceives a set of preferred resource through additional information fromeach of a plurality of UEs, the UE-B may first select availableresources or selected resources within a resource selection window ofthe UE-B based on the set of preferred resources. In this case, forexample, if the amount of available resources or selected resourcesselected based on additional information is less than a certain level,the UE-B may not use all or part of additional information. For example,the determination of which additional information to use or not to usemay depend on the implementation of the UE-B. For example, determinationof which additional information to use or not to use may be performedbased on a priority corresponding to additional information. Forexample, the UE-B may preferentially apply/use additional informationhaving a higher priority. For example, determination of which additionalinformation to use or not to use may be performed based on an RSRPmeasurement value corresponding to additional information. For example,the UE-B may preferentially apply/use additional informationcorresponding to a higher RSRP measurement value.

Considering the signaling overhead of the assistance information innetwork perspective, it is necessary to avoid a number of UEs transmithigh correlated assistance information. In other words, if a UE receivesthe assistance information from another UE, and the UE recognizes thatthe set of resources provided by the assistance information is the sameas the set of resources which the UE will transmit, then the UE can skipthe transmission of the assistance information.

Proposal: For the condition of UE-A's triggering the assistanceinformation, one or more of followings may be supported:

-   -   When UE-A triggers resource (re)selection for its own        transmission, or    -   When the RX quality at UE-A side from UE-B is smaller than a        certain threshold for a certain duration of time, or    -   When UE-A can recognize that the reserved resources of different        UE's are collided for a certain duration of time, or    -   UE-A may trigger the assistance information periodically with        (pre)configured period.

Proposal: It may be supported that UE-A skips triggering of theassistance information based on congestion control or the receivedassistance information from another UE.

Proposal: For the contents of UE-A's assistance information, one or moreof followings may be supported:

-   -   Reference point to indicate slot position, or    -   Contiguous or non-contiguous sub-channel(s), or    -   Contiguous or non-contiguous slot(s), or    -   RSRP value(s) (e.g., RSRP measurement based on the received        PSSCH DMRS at UE-A side), or    -   SCI contents related to sensing and its reception timing, or    -   Method to apply the assistance information for the resource        (re)selection procedure at RX UE side (e.g., resource set which        is not preferred for UE-A's reception, resource set which is        preferred not to be used by UE-B's transmission (e.g., when RSRP        measurement based on the container of the assistance information        at UE-B side is higher than the RSRP threshold, or when the        indicated RSRP values for the resource set is higher than the        RSRP threshold), resource set which is preferred for UE-B's        transmission)

Proposal: To determine the time-and-frequency resources provided byUE-A's assistance information, one or more of followings may beconsidered:

-   -   UE-A's selected resources, or    -   Slots for UE-A's periodic transmission (e.g.,        periodic/semi-persistent CSI reports, CG PUSCH, LTE V2X        SLSS/PSBCH or SPS PSCCH/PSSCH), or    -   FRIV, TRIV, and resource reservation period indicated by the        received SCI at UE-A side, or    -   TX pattern(s) overlapping with RX patterns

For example, TX pattern is determined by starting sub-channel index x,logical slot index y, number of sub-channels, TX priority, TX resourcereservation period, and resource reselection counter. These parameterscan be (pre)configured or predefined for the assistance information. RXpattern is determined by FRIV, TRIV, resource reservation period, RXpriority indicated in the received SCI at UE-A side. TX pattern can beindicated by the assistance information only if the RSRP measurementbased on the received PSSCH DMRS at UE-A side is higher than the RSRPthreshold which is given by a combination of TX priority and RXpriority.

Considering that the assistance information is used to indicate reservedresources, the form of the assistance information could be broadcast orgroupcast. Considering that the assistance information can include theset of slots where UE-A cannot perform SL reception, the form of theassistance information could be broadcast or groupcast or unicast. Forinstance, if the UE-A wants to transmit this information for theintended transmitter UE of UE-A, the assistance information could be aform of unicast or groupcast. Considering signaling overhead, it can beconsidered that UE-A transmit this information to a UE group rather thantransmitting this information to each UE separately. On the other hand,if the UE-A wants to transmit this information for the potentialtransmitter UE of UE-A, the form of the assistance information could bebroadcast or groupcast. Considering that the assistance information caninclude sensing results of UE-A, the form of the assistance informationcould be broadcast or groupcast.

Observation: Considering signaling overhead in system perspective, it isbeneficial that the assistance information is transmitted in a broadcastor groupcast manner.

Proposal: For the container of UE-A's assistance information, one ormore of followings is supported:

-   -   PSSCH with 2nd SCI format only (i.e., a TB is not transmitted),        or    -   MAC CE on PSSCH

It supports at least the case where the assistance information is notmultiplexed with other data of UE-A in the same TB. PSSCH containing theassistance information is at least for broadcast or connection-lessgroupcast.

Depending on the intended receiver UEs of the assistance information,the UE-B could use the assistance information based on the cast type ofits own transmission. For instance, if the assistance information isselected resources of UE-A or sensing results of UE-A, the assistanceinformation could be used for UE-B's resource (re)selection procedurefor broadcast/groupcast/unicast PSCCH/PSSCH transmission. On the otherhand, if the assistance information is resource set which is preferredor is not preferred for UE-A's reception, the assistance informationcould be used when the UE-B's PSCCH/PSSCH transmission is unicast or(connection-oriented) groupcast of which intended receiver is UE-A. Evenfor the broadcast, the assistance information sent by UE-A could be usedfor UE-B's resource (re)selection procedure to ensure UE-A can receivethe broadcast message sent by the UE-B.

Proposal: For the condition of using the assistance information at UE-Bside, one or more of followings is supported:

-   -   When UE-B triggers resource (re)selection for its own        transmission (i.e., UE-B has data to transmit), or    -   When the received assistance information is valid for UE-B        (e.g., target receiver of the assistance information includes        UE-B, and at least one resource provided by the assistance        information is within UE-B's resource reselection period), or    -   UE-B can use the assistance information for all the cast types        of PSCCH/PSSCH transmissions.

Proposal: When UE-B receives updated assistance information from thesame UE, UE-B can perform resource (re)selection procedure again byusing the updated assistance information in case of one or more offollowing conditions:

-   -   When the updated assistance information indicates resources with        priority value smaller than a (pre)configured threshold, or    -   When the remaining PDB of UE-B's transmission is higher than a        (pre)configured threshold, or    -   When the updated assistance information includes slot positions        where UE-A cannot perform SL reception, or    -   When the amount of changed resources provided across different        assistance information is higher than a certain threshold.

Proposal: For UE-B's resource (re)selection procedure, the UE-B uses theassistance information as one or more of following ways:

-   -   UE-B determines candidate resources based on the received SCI at        UE-B side and the resource set provided by the assistance        information (e.g., UE-B (additionally) exclude TX pattern(s)        overlapping with the resource set provided by the assistance        information from the candidate resource set if the corresponding        RSRP measurement is higher than the RSRP threshold. The RSRP        measurement of the resource set is based on DMRS of PSSCH        containing the assistance information, or the RSRP measurement        of the resource set is given by the assistance information, or        the RSRP measurement of the resource set is always infinity.        UE-B determines final candidate resource set by using the        intersection of candidate resource set based on the received SCI        and the resource set provided by the assistance information), or    -   UE-B determines selected resources based on a resource set        provided by the assistance information after deciding candidate        resource set based on the received SCI at UE-B side (e.g., UE-B        determines selected resources to avoid the resource set provided        by the assistance information, or UE-B determines selected        resource among the candidate resources to include all or a        subset of the resource set provided by the assistance        information).

Proposal: For UE-B's resource (re)selection procedure, the ratio ofcandidate resources over a resource selection window is determined asone or more of following ways:

-   -   UE-B determines the candidate resource ratio based on only the        received SCI (e.g., if the ratio of the candidate resources        determined based on the received SCI only is smaller than X %,        the RSRP threshold is boosted. Otherwise, RSRP threshold is not        boosted. The resource set provided by the assistance information        can be used, or the resource set provided by the assistance        information is no longer used), or    -   UE-B determines the candidate resource ratio based on both the        received SCI and the assistance information (e.g., if the ratio        of the candidate resources determined based on the received SCI        only is smaller than X %, the RSRP threshold for the received        SCI is boosted. Else if the ratio of the candidate resources        determined based on the received SCI and the assistance        information is smaller than Y %, the RSRP threshold for the        assistance information is boosted, or the resource set provided        by the assistance information is no longer used).

Proposal: For UE-B's resource (re)selection procedure, the RX pattern(s)associated with the non-monitored slot is determined as one or more offollowing ways:

-   -   Reuse Rel-16 mechanism (i.e., RX patterns are all the        sub-channels in slots associated with the non-monitored-slot        based on all the (pre)configured resource reservation period        values), or    -   RX patterns are derived by the resource set provided by the        assistance information, or    -   Among the slots associated with the non-monitored slot, if there        is resource(s) provided by the assistance information, the RX        pattern is derived by the assistance information, otherwise, the        RX pattern consists of all the sub-channels.

Meanwhile, a UE transmitting additional information that can be used ina resource (re)selection procedure for PSCCH/PSSCH transmission ofanother UE may be predefined or (pre-)configured. Herein, for example, aprocedure for performing/establishing a relationship/connection betweena UE transmitting additional information (hereinafter referred to asUE-A) and a UE receiving the additional information and/or using theadditional information for resource reselection (hereinafter referred toas UE-B) may be required. For example, the UE-A capable of transmittingadditional information may be a UE configured to be capable of orsupported to transmit additional information as UE capability. Forexample, the UE-A may receive, from a base station or another UE,information/message related to UE capability including informationindicating that transmission of additional information is possible orinformation indicating that transmission of additional information issupported. For example, if a battery status and/or the amount of batteryof the UE is greater than or equal to a certain level, the UE maydetermine that it has the ability to transmit additional information.For example, if the type of the UE is a specific UE type (e.g., vehicletype, vehicle height, antenna height, RSU status, etc.), the UE maydetermine that it has the ability to transmit additional information.For example, if the UE is a UE (e.g., a bus) moving along a certainroute, the UE may determine that it has the ability to transmitadditional information. For example, if the UE is a UE (e.g., RSU) witha fixed location, the UE may determine that it has the ability totransmit additional information. That is, the UE that satisfies at leastone of the above conditions can transmit additional information.

For example, the UE-A capable of transmitting additional information maybe selected/determined based on the following procedure. For example,the UE may perform a process of checking whether there is a UE alreadytransmitting additional information in the vicinity. More specifically,for example, the UE may attempt to detect a PSCCH/PSSCH corresponding toadditional information in a specific time window (e.g., a(pre-)configured slot period), and the UE may decide/determine whetherthere is a UE transmitting additional information in the vicinity of theUE based on whether a signal corresponding to additional information isdetected within the specific time window and/or based on an RSRP valueor received power of the signal. For example, if the UE detects aPSCCH/PSSCH corresponding to additional information within the specifictime window, and/or if an RSRP measurement value for the PSCCH or thePSSCH is greater than or equal to a (pre-)configured threshold, the UEmay decide/determine that there is a UE transmitting additionalinformation in the vicinity of the UE. Otherwise, the UE maydecide/determine that there is no UE transmitting additional informationin the vicinity of the UE. For example, a first UE may transmit a signalfor checking whether there is a second UE transmitting additionalinformation. In this case, for example, the second UE which has receivedthe signal transmitted by the first UE may transmit a response to thesignal to the first UE, under a specific condition. For example, thespecific condition may be a case in which the second UE which hasreceived the signal is a UE transmitting additional information, a UEcapable of transmitting additional information or a UE allowed totransmit additional information. For example, the specific condition maybe a case in which the second UE which has received the signal is a UEwhich is receiving additional information from another UE or a UE whichhas received additional information from another UE. For example, thespecific condition may be a case in which the second UE which hasreceived the signal (i) is not currently performing resource(re)selection based on additional information, and (ii) is a UE capableof performing resource (re)selection using additional information (e.g.,a UE capable of performing resource (re)selection using additionalinformation in terms of UE capability and/or in terms of beingconfigured additional information-based resource reselection operation).For example, if the second UE transmitting additional informationtransmits a response signal, the response signal may include informationfor the first UE to receive additional information transmitted by thesecond UE. For example, if the second UE receiving additionalinformation from another UE transmits a response signal, the responsesignal may include information (e.g., information of a UE transmittingadditional information and/or indicator information for additionalinformation, etc.) for the first UE to receive additional informationthat the second UE receives from another UE. For example, a window(e.g., the size of the window may be (pre-)configured) for the first UEto receive a response signal, in response to a signal for identifyingthe second UE transmitting additional information, may be configured forthe first UE. In this case, if the first UE fails to receive theresponse signal within the window, the first UE may decide/determinethat there is no UE transmitting additional information in the vicinityof the first UE. For example, even if the first UE receives the responsesignal, the first UE may decide/determine that there is no UEtransmitting additional information in the vicinity of the first UE ifthe response signal does not include information regarding a UE whichhas transmitted additional information and/or information regarding amethod of receiving additional information.

For example, if the first UE decides/determines that there is the secondUE transmitting additional information in the vicinity of the first UE,the first UE may perform a signaling/procedure for requestinginformation for receiving additional information from the second UEtransmitting the additional information. For example, the first UE maytransmit a signal requesting to be included in an additional informationreception group to the second UE which is transmitting additionalinformation, and in response to the request, the second UE which istransmitting the additional information may inform the first UE ofwhether or not the first UE is included in the additional informationreception group and/or a result thereof. For example, the first UE maytransmit a signal requesting to be included in an additional informationreception group to the second UE which is transmitting additionalinformation, and in response to the request, the second UE which istransmitting the additional information may inform the first UE of aresult that the first UE cannot be included in the additionalinformation reception group. For example, even if the first UEdecides/determines that there is the second UE transmitting additionalinformation in the vicinity of the first UE, the first UE may perform asignaling/procedure for declaring that it is a UE transmittingadditional information if the first UE cannot receive additionalinformation from another UE.

For example, if the first UE decides/determines that there is no secondUE transmitting additional information in the vicinity of the first UE,the first UE may transmit a signal declaring that it is a UEtransmitting additional information (hereinafter, a declaration signal).For example, the declaration signal may include information forreceiving additional information. For example, if a third UE which hasreceived the declaration signal wishes to receive additional informationfrom the first UE, the third UE may transmit a response signal to thefirst UE. For example, the response signal may include transmissionpacket information of the third UE (e.g., including a priority value,resource reselection window information, sensing window information,(remaining) PDB information, resource reselection counter information,the (maximum) number of retransmissions, the number of subchannels,resource reservation period information, a cast type, whether or notHARQ-ACK feedback is enabled, a HARQ-ACK feedback option, a QoSparameter, a (L1) source ID, and/or a (L1) destination ID, etc.). Forexample, the UE which intends to transmit additional information mayconfigure a recipient group to which additional information is to bereceived based on the response signal, and the UE which intends totransmit additional information may transmit information related to therecipient group and/or whether additional information can be received tothe UE which has transmitted the response signal.

For example, the signaling/procedure for declaring that the UE is a UEtransmitting additional information and the signaling/procedure forconfirming that the UE transmitting additional information exists arounda UE may be integrated. In this case, if a UE transmitting additionalinformation or a UE already receiving additional information receivesthe declaration signal, the UE may inform that there is a UE alreadytransmitting additional information, in response to the declarationsignal.

For example, the declaration signal, the response signal to thedeclaration signal, the detection signal for detecting UE transmittingadditional information, and the response signal to the detection signalmay be transmitted in the form of first SCI and/or second SCI and/or aPSSCH and/or a PSFCH. For example, the declaration signal, the responsesignal to the declaration signal, the detection signal for detecting UEtransmitting additional information, and the response signal to thedetection signal may be transmitted in the form of a MAC message,PC5-RRC signaling, or PC5 S signaling. In the present disclosure, thesignal may be replaced with other terms such as a packet, controlinformation, a message, or information according to a layer throughwhich the signal is transmitted.

Meanwhile, a UE capable of transmitting additional information or a UEtransmitting additional information (hereinafter referred to as anadditional information transmitting UE) may be determined in advancewhen UEs are developed. For example, an RSU may be installed at anintersection or the like, and the RSU may serve to transmit additionalinformation to surroundings. Meanwhile, depending on a road condition,shape, distribution of UEs, etc., the additional informationtransmitting UE may explicitly or implicitly determine a UE group, andthe additional information transmitting UE may transmit additionalinformation to each UE group. For example, in the process of configuringthe UE group, a UE desiring to receive additional information maytransmit, to the additional information transmitting UE, at least one ofan RSRP measurement value for a signal transmitted by the additionalinformation transmitting UE, angle of arrival (AOA) information for thesignal transmitted by the additional information transmitting UE and/orlocation information of the UE. Thereafter, for example, the additionalinformation transmitting UE may explicitly or implicitlyconfigure/determine a UE group based on the information, and theadditional information transmitting UE may specify additionalinformation for each UE group. For example, the additional informationtransmitting UE may instruct/transmit information regarding the UE groupto respective UEs again. For example, when the additional informationtransmitting UE transmits additional information, the additionalinformation may include information regarding a UE group correspondingto the additional information. For example, in the process ofconfiguring the UE group, the additional information transmitting UE mayprovide/transmit information regarding the UE group to neighboring UEs.For example, the information regarding the UE group may include at leastone of location information of a UE to belong to the UE group (e.g.,single or multiple ZONE IDs and/or information regarding a size of theZONE and/or shape/angle of the ZONE), direction information of a UE tobelong to the UE group with respect to the additional informationtransmitting UE (e.g., an AOA value or the range of AOA values measuredby the receiving UE based on a signal of the UE transmitting additionalinformation), and/or an RSRP measurement value or the range of RSRPmeasurement values measured by the UE to belong to the UE group based onthe signal transmitted by the additional information transmitting UE.For example, the additional information transmitting UE mayprovide/transmit set information regarding the ZONE for each UE group.For example, the shape of the ZONE may be expressed in the form of agrid of the actual location of the UE with longitude and latitude axes.For example, the shape of the ZONE may be expressed as a grid shapedistorted by a specific (indicated) angle with respect to longitude andlatitude axes. For example, the additional information transmitting UEmay transmit additional information to a single UE group or a pluralityof UE groups, and each additional information may include information(e.g., a UE group ID or a combination of the parameters) for acorresponding UE group. For example, a UE which has received additionalinformation may select/determine additional information to be used orvalid additional information, based on at least one of an RSRPmeasurement value measured based on a signal transmitted by theadditional information transmitting UE, direction information from theadditional information transmitting UE, and/or location information ofeach UE. For example, a UE which has received additional information mayinfer/determine a UE group to which it belongs and select/determineadditional information to be used or valid additional information, basedon at least one of an RSRP measurement value measured based on a signaltransmitted by the additional information transmitting UE, directioninformation from the additional information transmitting UE, and/orlocation information of each UE.

Meanwhile, in the next-generation system, a third UE may recognize aresource conflict between different UEs (e.g., PSCCH and/or PSSCHresources overlap and/or UEs communicating with each other perform SLtransmission at the same time). In this case, for example, the third UEmay inform the UEs of the resource conflict situation. Or, for example,in this case, the third UE may transmit SL HARQ-ACK feedback (e.g., HARQACK information or HARQ NACK information) instead of the UEs.

Meanwhile, in the case of the groupcast HARQ-ACK feedback option 2, aPSFCH resource may be determined based on a member ID (i.e., M_(ID) ofTable 6) value provided to a groupcast PSSCH receiving UE. For example,the UE may transmit HARQ-ACK (e.g., ACK or NACK) based on Table 5 andTables 6A-6D.

TABLE 5 A UE can be indicated by an SCI format scheduling a PSSCHreception, in one or more sub-channels from a number of N_(subch)^(PSSCH) sub-channels, to transmit a PSFCH with HARQ-ACK information inresponse to the PSSCH reception. The UE provides HARQ-ACK informationthat includes ACK or NACK, or only NACK. A UE can be provided, bysl-PSFCH-Period-r16, a number of slots in a resource pool for a periodof PSFCH transmission occasion resources. If the number is zero, PSFCHtransmissions from the UE in the resource pool are disabled. A UEexpects that a slot t′_(k) ^(SL) (0 ≤ k < T′_(max) ) has a PSFCHtransmission occasion resource if k mod N_(PSSCH) ^(PSFCH =) 0, wheret′_(k) ^(SL) is defined in [6, TS 38.214], and T′_(max) is a number ofslots that belong to the resource pool within 10240 msec according to[6, TS 38.214], and N_(PSSCH) ^(PSFCH) is provided bysl-PSFCH-Period-r16. A UE may be indicated by higher layers to nottransmit a PSFCH in response to a PSSCH reception [11, TS 38.321]. If aUE receives a PSSCH in a resource pool and the HARQ feedbackenabled/disabled indicator field in an associated SCI format 2-A or aSCI format 2-B has value 1 [5, TS 38.212], the UE provides the HARQ-ACKinformation in a PSFCH transmission in the resource pool. The UEtransmits the PSFCH in a first slot that includes PSFCH resources and isat least a number of slots, provided by sl-MinTimeGapPSFCH-r16, of theresource pool after a last slot of the PSSCH reception. A UE is providedby sl-PSFCH-RB-Set-r16 a set of M_(PRB, set) ^(PSFCH) PRBs in a resourcepool for PSFCH transmission in a PRB of the resource pool. For a numberof N_(subch) sub-channels for the resource pool, provided bysl-NumSubchannel, and a number of PSSCH slots associated with a PSFCHslot that is less than or equal to N_(PSSCH) ^(PSFCH), the UE allocatesthe [(i + j · N_(PSSCH) ^(PSFCH)) · M_(subch, slot) ^(PSFCH), (i + 1 + j· N_(PSSCH) ^(PSFCH)) · M_(subch, slot) ^(PSFCH) − 1] PRBs from theM_(PRB, set) ^(PSFCH) PRBs to slot i among the PSSCH slots associatedwith the PSFCH slot and sub-channel j, where M_(subch, slot) ^(PSFCH) =M_(PRB, set) ^(PSFCH)/(N_(subch) · N_(PSSCH) ^(PSFCH)), 0 ≤ i <N_(PSSCH) ^(PSFCH) , 0 ≤ j < N_(subch), and the allocation starts in anascending order of i and continues in an ascending order of j. The UEexpects that M_(PRB, set) ^(PSFCH) is a multiple of N_(subch) ·N_(PSSCH) ^(PSFCH). A UE determines a number of PSFCH resourcesavailable for multiplexing HARQ-ACK information in a PSFCH transmissionas R_(PRB, CS) ^(PSFCH) = N_(type) ^(PSFCH) · M_(subch, slot) ^(PSFCH) ·N_(CS) ^(PSFCH) where N_(CS) ^(PSFCH) is a number of cyclic shift pairsfor the resource pool and, based on an indication by higher layers,  N_(type) ^(PSFCH) = 1 and the M_(subch, slot) ^(PSFCH) PRBs areassociated with the starting sub-channel of the corresponding PSSCH  N_(type) ^(PSFCH) = N_(subch) ^(PSSCH) and the N_(subch) ^(PSSCH) ·M_(subch, slot) ^(PSFCH) PRBs are associated with one or moresub-channels from the N_(subch) ^(PSSCH) sub-channels of thecorresponding PSSCH The PSFCH resources are first indexed according toan ascending order of the PRB index, from the N_(type) ^(PSFCH) ·M_(subch, slot) ^(PSFCH) PRBs, and then according to an ascending orderof the cyclic shift pair index from the N_(CS) ^(PSFCH) cyclic shiftpairs.

TABLE 6A A UE determines an index of a PSFCH resource for a PSFCHtransmission in response to a PSSCH reception as (P_(ID) +M_(ID))modR_(PRB, CS) ^(PSFCH) where P_(ID) is a physical layer sourceID provided by SCI format 2-A or 2-B [5, TS 38.212] scheduling the PSSCHreception, and M_(ID) is the identity of the UE receiving the PSSCH asindicated by higher layers if the UE detects a SCI format 2-A with Casttype indicator field value of “01”; otherwise, M_(ID) is zero. A UEdetermines a m₀ value, for computing a value of cyclic shift α [4, TS38.211], from a cyclic shift pair index corresponding to a PSFCHresource index and from N_(CS) ^(PSFCH) using Table 6B. A UE determinesa m_(cs) value, for computing a value of cyclic shift α [4, TS 38.211],as in Table 6C if the UE detects a SCI format 2-A with Cast typeindicator field value of “01” or “10”, or as in Table 6D if the UEdetects a SCI format 2-B or a SCI format 2-A with Cast type indicatorfield value of “11”. The UE applies one cyclic shift from a cyclic shiftpair to a sequence used for the PSFCH transmission [4, TS 38.211].

TABLE 6B Set of cyclic shift pairs m₀ Cyclic Cyclic Cyclic Cyclic CyclicCyclic Shift Shift Shift Shift Shift Shift Pair Pair Pair Pair Pair PairN_(CS) ^(PSFCH) Index 0 Index 1 Index 2 Index 3 Index 4 Index 5 1 0 — —— — — 2 0 3 — — — — 3 0 2 4 — — — 6 0 1 2 3 4 5

TABLE 6C Mapping of HARQ-ACK information bit values to a cyclic shift,from a cyclic shift pair, of a sequence for a PSFCH transmission whenHARQ-ACK information includes ACK or NACK HARQ-ACK Value 0 (NACK) 1(ACK) Sequence cyclic shift 0 6

TABLE 6D Mapping of HARQ-ACK information bit values to a cyclic shift,from a cyclic shift pair, of a sequence for a PSFCH transmission whenHARQ-ACK information includes only NACK HARQ-ACK Value 0 (NACK) 1 (ACK)Sequence cyclic shift 0 N/A

Meanwhile, in a situation in which a third UE recognizes a resourceconflict between other UEs, the third UE may not know member IDinformation (i.e., M_(ID)) for each UE. In this case, it may not beappropriate for the third UE to transmit NACK instead of the UEs. Forexample, the third UE which recognizes the resource conflict may belongto the same UE group (i.e., a set of UEs receiving the same groupcastPSSCH). For example, regardless of whether the third UE successfullydecodes a TB transmitted through a groupcast PSSCH, if a resourceconflict is recognized at a time or resource occupied for the groupcastPSSCH, the third UE may transmit, to a UE which has transmitted thegroupcast PSSCH, NACK by using a PSFCH resource allocated to itself(i.e., the third UE). Herein, for example, the third UE mayselect/determine the PSFCH resource allocated to itself (i.e., the thirdUE) based on the M_(ID) provided to itself (i.e., the third UE).

Meanwhile, in the case of the groupcast HARQ-ACK feedback option 1, notall receiving UEs transmit SL HARQ-ACK feedback. Specifically, forexample, only if (i) a receiving UE fails to decode a PSSCH, and (ii)the distance between the center location of a ZONE indicated by SCI andthe receiving UE is smaller than a communication range requirementindicated by the SCI, the receiving UE may transmit NACK to thetransmitting UE. Meanwhile, in case that a third UE which recognizes aresource conflict and transmits NACK instead of other UEs is outside acommunication range requirement with respect to the center of a ZONE inwhich a transmitting UE is located, the third UE may recognize aresource conflict that is not valid from the point of view of a UEwithin the communication range requirement. Specifically, for example,although it is a non-conflict resource from the point of view of the UEwithin the communication range requirement, the third UE outside thecommunication range requirement may determine that it is a conflictresource. For example, although it is a conflict resource from the pointof view of the UE within the communication range requirement, the thirdUE outside the communication range requirement may determine that it isa non-conflict resource. Therefore, for example, the third UE whichrecognizes a resource conflict for a groupcast PSSCH may be a UE locatedin a ZONE related to a ZONE ID included in SCI corresponding to thegroupcast PSSCH. For example, the third UE which recognizes a resourceconflict for a groupcast PSSCH may be a UE located within acommunication range requirement included in SCI, from the center of aZONE related to a ZONE ID included in the SCI corresponding to thegroupcast PSSCH. For example, the third UE which recognizes a resourceconflict for a groupcast PSSCH may be a UE located within a(pre-)configured distance (range), from the center of a ZONE related toa ZONE ID included in SCI corresponding to the groupcast PSSCH. Forexample, the third UE which recognizes a resource conflict for agroupcast PSSCH may be a UE whose RSRP value measured based on a PSCCHDMRS or a PSSCH DMRS corresponding to the groupcast PSSCH is greaterthan or equal to a (pre-)configured threshold. For example, the third UEmay be one of UEs receiving the groupcast PSSCH, and the third UE maytransmit NACK to the transmitting UE upon recognizing a resourceconflict, regardless of whether or not a TB transmitted through a PSSCHis successfully decoded. Meanwhile, the UE-A may measure/instruct aresource conflict for a previously selected/reserved resource of theUE-B. For example, in this case, the UE-A may determine a resourceconflict only if the previously selected/reserved resource correspondsto initial transmission. For example, the initial transmission may be aPSSCH resource successfully received for the first time for a TB fromthe point of view of the UE-A. That is, for example, a half-duplexproblem and/or a resource conflict may not be determined for aretransmission resource of the UE-B with respect to the UE-A. Similarly,the UE-A may not transmit a resource conflict indicator for the resourceto the UE-B.

For example, an indicator indicating whether or not additionalinformation is included may be included in first SCI and/or second SCIcorresponding to the additional information. For example, the indicatormay indicate UE group information corresponding to additionalinformation. For example, if the UE determines that received SCIindicates additional information for the UE, the UE may decode or expectto decode a PSSCH to obtain additional information even if an L1destination ID indicated by second SCI is not for the UE.

In an embodiment of the present disclosure, the UE may obtain an RSRPmeasurement value used when generating additional information, based ona PSCCH DMRS and/or a PSSCH DMRS. For example, when the UE-A generatesadditional information, the type of a reference signal referred to whenmeasuring RSRP may be (pre-)configured. For example, when the UE-Agenerates additional information, the type of a reference signalreferred to when measuring RSRP may be configured through PC5-RRCsignaling between the UE-A and the UE-B. For example, when the UE-Agenerates additional information, the UE-B may indicate the type of areference signal referred to when measuring RSRP to the UE-A whenrequesting additional information. For example, when the UE-A generatesadditional information, the type of a reference signal referred to whenmeasuring RSRP may be configured for a TX resource pool for transmissionof the UE-B provided by the UE-B to the UE-A. For example, when the UE-Agenerates additional information, the type of a reference signalreferred to when measuring RSRP may be configured for a resource pool inwhich the UE-A transmits additional information. For example, when theUE-A generates additional information, the type of a reference signalreferred to when measuring RSRP may be configured for a resource pool inwhich the UE-A generates additional information.

Meanwhile, the UE-A may indicate resource conflict information for aresource indicated by additional information and/or SCI of the UE-B. Inparticular, in the case of resource overlap, the UE-A may determine aresource conflict based on an RSRP measurement value. For example, if anRSRP measurement value of a PSCCH/PSSCH resource overlapping atransmission resource and/or a reserved resource of the UE-B is greaterthan or equal to a specific threshold, the UE-A may determine a resourceconflict and indicate it to the UE-B. For example, the specificthreshold may be determined according to a transmission priority and areception priority value. For example, the reception priority may be apriority value indicated by SCI for the PSCCH/PSSCH overlapping thetransmission resource of the UE-B. For example, the transmissionpriority may be a priority value indicated by SCI for the transmissionresource of the UE-B.

FIG. 13 shows a procedure for a UE to perform SL communication based onassistance information, based on an embodiment of the presentdisclosure. The embodiment of FIG. 13 may be combined with variousembodiments of the present disclosure.

Referring to FIG. 13 , in step S1310, the UE-B may receive SCI from theUE-A through a PSCCH. For example, the SCI may include information forscheduling a PSSCH. In step S1320, the UE-B may receive assistanceinformation from the UE-A through the PSSCH. For example, the assistanceinformation may be included in a MAC PDU. For example, the assistanceinformation may include information proposed in various embodiments ofthe present disclosure. In step S1330, the UE-B may select a SL resourcebased on the assistance information.

In step S1340, the UE-B may transmit a PSCCH and/or a PSSCH to the UE-Cbased on the selected SL resource. Alternatively/additionally, in stepS1350, the UE-B may transmit a PSCCH and/or a PSSCH to the UE-A based onthe selected SL resource.

FIG. 14 shows a procedure for a UE to perform SL communication based onassistance information, based on an embodiment of the presentdisclosure. The embodiment of FIG. 14 may be combined with variousembodiments of the present disclosure.

Referring to FIG. 14 , in step S1410, the UE-B may transmit anadditional information request to the UE-A. For example, the additionalinformation request may include information proposed in variousembodiments of the present disclosure.

In step S1420, the UE-A may generate additional information based on theadditional information request. For example, the UE-A may generateadditional information related to specific information, based on thespecific information included in the additional information request.

In step S1430, the UE-A may transmit first SCI to the UE-B through aPSCCH. For example, the first SCI may include information for schedulinga PSSCH. In step S1440, the UE-A may transmit additional information tothe UE-B through the PSSCH. For example, the additional information maybe included in a MAC PDU. For example, the additional information may beincluded in second SCI. For example, the additional information mayinclude information proposed in various embodiments of the presentdisclosure. In step S1450, the UE-B may select SL resource(s) based onthe additional information.

Based on various embodiments of the present disclosure, the UE-B mayefficiently perform (re)selection of resource(s) for transmission by theUE-B based on assistance information transmitted by the UE-A.Furthermore, if a specific condition is satisfied, the UE-A may transmitassistance information to the UE-B. Through this, it is possible tosolve a problem in which radio resources are wasted due to the UE-Aindiscriminately transmitting assistance information. Furthermore, theUE-A may generate assistance information based on an assistanceinformation request transmitted by the UE-B. Through this, from thepoint of view of the UE-B, necessary assistance information can begenerated, and the UE-B can efficiently select SL resource(s) based onassistance information requested by the UE-B.

FIG. 15 shows a method for performing wireless communication by a firstdevice, based on an embodiment of the present disclosure. The embodimentof FIG. 15 may be combined with various embodiments of the presentdisclosure.

Referring to FIG. 15 , in step S1510, the first device may receive, froma second device, an assistance information request. In step S1520, thefirst device may generate assistance information based on the assistanceinformation request. In step S1530, the first device may transmit, tothe second device through a physical sidelink control channel (PSCCH),first sidelink control information (SCI) including schedulinginformation for a physical sidelink shared channel (PSSCH). For example,the first SCI may include information related to frequency resourceassignment, information related to time resource assignment, informationrelated to a demodulation reference signal (DMRS) pattern, andinformation related to modulation and coding scheme (MCS). In stepS1540, the first device may transmit, to the second device through thePSSCH, the assistance information in response to the assistanceinformation request. For example, the assistance information may includeinformation for sidelink (SL) resource selection of the second device.

For example, the second SCI including the assistance information may betransmitted through the PSSCH. For example, based on that the second SCIincluding the assistance information is transmitted through the PSSCH, amedium access control (MAC) protocol data unit (PDU) may not betransmitted through the PSSCH.

For example, based on the assistance information request includinginformation related to a reference transmission priority, the assistanceinformation related to the reference transmission priority may begenerated.

For example, based on the assistance information request includinginformation related to a reference resource selection window, theassistance information including information related to at least oneresource within the reference resource selection window may begenerated.

For example, based on the assistance information request includinginformation related to a reference resource reservation period, theassistance information including information related to at least oneresource having the reference resource reservation period may begenerated.

For example, based on the assistance information request includinginformation related to a reference number of subchannels for PSSCHtransmission, the assistance information including information relatedto at least one resource having the reference number of subchannels maybe generated.

For example, based on the assistance information request includinginformation related to a cast type, the assistance information relatedto the cast type may be generated.

For example, based on the assistance information request includinginformation related to a service type, the assistance informationrelated to the service type may be generated.

For example, based on the assistance information request includinginformation related to a packet delay budget (PDB) for assistanceinformation, the assistance information may be transmitted to the seconddevice within the PDB.

For example, based on the assistance information request includinginformation related to a reference packet delay budget (PDB), theassistance information including information related to at least oneresource within the reference PDB may be generated.

For example, a priority related to transmission of the assistanceinformation may be configured for each resource pool.

For example, transmission of the assistance information may be allowedin N resources preceding in time among a plurality of resources, and avalue of N may be a positive integer configured for the first device.

The proposed method can be applied to the device(s) based on variousembodiments of the present disclosure. First, the processor 102 of thefirst device 100 may control the transceiver 106 to receive, from asecond device, an assistance information request. In addition, theprocessor 102 of the first device 100 may generate assistanceinformation based on the assistance information request. In addition,the processor 102 of the first device 100 may control the transceiver106 to transmit, to the second device through a physical sidelinkcontrol channel (PSCCH), first sidelink control information (SCI)including scheduling information for a physical sidelink shared channel(PSSCH). For example, the first SCI may include information related tofrequency resource assignment, information related to time resourceassignment, information related to a demodulation reference signal(DMRS) pattern, and information related to modulation and coding scheme(MCS). In addition, the processor 102 of the first device 100 maycontrol the transceiver 106 to transmit, to the second device throughthe PSSCH, the assistance information in response to the assistanceinformation request. For example, the assistance information may includeinformation for sidelink (SL) resource selection of the second device.

Based on an embodiment of the present disclosure, a first device adaptedto perform wireless communication may be provided. For example, thefirst device may comprise: one or more memories storing instructions;one or more transceivers; and one or more processors connected to theone or more memories and the one or more transceivers. For example, theone or more processors may execute the instructions to: receive, from asecond device, an assistance information request; generate assistanceinformation based on the assistance information request; transmit, tothe second device through a physical sidelink control channel (PSCCH),first sidelink control information (SCI) including schedulinginformation for a physical sidelink shared channel (PSSCH), wherein thefirst SCI includes information related to frequency resource assignment,information related to time resource assignment, information related toa demodulation reference signal (DMRS) pattern, and information relatedto modulation and coding scheme (MCS); and transmit, to the seconddevice through the PSSCH, the assistance information in response to theassistance information request. For example, the assistance informationmay include information for sidelink (SL) resource selection of thesecond device.

Based on an embodiment of the present disclosure, an apparatus adaptedto control a first user equipment (UE) may be provided. For example, theapparatus may comprise: one or more processors; and one or more memoriesoperably connected to the one or more processors and storinginstructions. For example, the one or more processors may execute theinstructions to: receive, from a second UE, an assistance informationrequest; generate assistance information based on the assistanceinformation request; transmit, to the second UE through a physicalsidelink control channel (PSCCH), first sidelink control information(SCI) including scheduling information for a physical sidelink sharedchannel (PSSCH), wherein the first SCI includes information related tofrequency resource assignment, information related to time resourceassignment, information related to a demodulation reference signal(DMRS) pattern, and information related to modulation and coding scheme(MCS); and transmit, to the second UE through the PSSCH, the assistanceinformation in response to the assistance information request. Forexample, the assistance information may include information for sidelink(SL) resource selection of the second device.

Based on an embodiment of the present disclosure, a non-transitorycomputer-readable storage medium storing instructions may be provided.For example, the instructions, when executed, may cause a first deviceto: receive, from a second device, an assistance information request;generate assistance information based on the assistance informationrequest; transmit, to the second device through a physical sidelinkcontrol channel (PSCCH), first sidelink control information (SCI)including scheduling information for a physical sidelink shared channel(PSSCH), wherein the first SCI includes information related to frequencyresource assignment, information related to time resource assignment,information related to a demodulation reference signal (DMRS) pattern,and information related to modulation and coding scheme (MCS); andtransmit, to the second device through the PSSCH, the assistanceinformation in response to the assistance information request. Forexample, the assistance information may include information for sidelink(SL) resource selection of the second device.

FIG. 16 shows a method for performing wireless communication by a seconddevice, based on an embodiment of the present disclosure. The embodimentof FIG. 16 may be combined with various embodiments of the presentdisclosure.

Referring to FIG. 16 , in step S1610, the second device may transmit, toa first device, an assistance information request. In step S1620, thesecond device may receive, from the first device through a physicalsidelink control channel (PSCCH), sidelink control information (SCI)including scheduling information for a physical sidelink shared channel(PSSCH). For example, the SCI may include information related tofrequency resource assignment, information related to time resourceassignment, information related to a demodulation reference signal(DMRS) pattern, and information related to modulation and coding scheme(MCS). In step S1630, the second device may receive, from the firstdevice through the PSSCH, assistance information in response to theassistance information request. In step S1640, the second device mayselect a sidelink (SL) resource based on at least one of the SCI or theassistance information. For example, the assistance information mayinclude information for selecting the SL resource, and the assistanceinformation may be generated based on the assistance informationrequest.

The proposed method can be applied to the device(s) based on variousembodiments of the present disclosure. First, the processor 202 of thesecond device 200 may control the transceiver 206 to transmit, to afirst device, an assistance information request. In addition, theprocessor 202 of the second device 200 may control the transceiver 206to receive, from the first device through a physical sidelink controlchannel (PSCCH), sidelink control information (SCI) including schedulinginformation for a physical sidelink shared channel (PSSCH). For example,the SCI may include information related to frequency resourceassignment, information related to time resource assignment, informationrelated to a demodulation reference signal (DMRS) pattern, andinformation related to modulation and coding scheme (MCS). In addition,the processor 202 of the second device 200 may control the transceiver206 to receive, from the first device through the PSSCH, assistanceinformation in response to the assistance information request. Inaddition, the processor 202 of the second device 200 may select asidelink (SL) resource based on at least one of the SCI or theassistance information. For example, the assistance information mayinclude information for selecting the SL resource, and the assistanceinformation may be generated based on the assistance informationrequest.

Based on an embodiment of the present disclosure, a second deviceadapted to perform wireless communication may be provided. For example,the second device may comprise: one or more memories storinginstructions; one or more transceivers; and one or more processorsconnected to the one or more memories and the one or more transceivers.For example, the one or more processors may execute the instructions to:transmit, to a first device, an assistance information request; receive,from the first device through a physical sidelink control channel(PSCCH), sidelink control information (SCI) including schedulinginformation for a physical sidelink shared channel (PSSCH), wherein theSCI includes information related to frequency resource assignment,information related to time resource assignment, information related toa demodulation reference signal (DMRS) pattern, and information relatedto modulation and coding scheme (MCS); receive, from the first devicethrough the PSSCH, assistance information in response to the assistanceinformation request; and select a sidelink (SL) resource based on atleast one of the SCI or the assistance information. For example, theassistance information may include information for selecting the SLresource, and the assistance information may be generated based on theassistance information request.

Based on an embodiment of the present disclosure, an apparatus adaptedto control a second user equipment (UE) may be provided. For example,the apparatus may comprise: one or more processors; and one or morememories operably connected to the one or more processors and storinginstructions. For example, the one or more processors may execute theinstructions to: transmit, to a first UE, an assistance informationrequest; receive, from the first UE through a physical sidelink controlchannel (PSCCH), sidelink control information (SCI) including schedulinginformation for a physical sidelink shared channel (PSSCH), wherein theSCI includes information related to frequency resource assignment,information related to time resource assignment, information related toa demodulation reference signal (DMRS) pattern, and information relatedto modulation and coding scheme (MCS); receive, from the first UEthrough the PSSCH, assistance information in response to the assistanceinformation request; and select a sidelink (SL) resource based on atleast one of the SCI or the assistance information. For example, theassistance information may include information for selecting the SLresource, and the assistance information may be generated based on theassistance information request.

Based on an embodiment of the present disclosure, a non-transitorycomputer-readable storage medium storing instructions may be provided.For example, the instructions, when executed, may cause a second deviceto: transmit, to a first device, an assistance information request;receive, from the first device through a physical sidelink controlchannel (PSCCH), sidelink control information (SCI) including schedulinginformation for a physical sidelink shared channel (PSSCH), wherein theSCI includes information related to frequency resource assignment,information related to time resource assignment, information related toa demodulation reference signal (DMRS) pattern, and information relatedto modulation and coding scheme (MCS); receive, from the first devicethrough the PSSCH, assistance information in response to the assistanceinformation request; and select a sidelink (SL) resource based on atleast one of the SCI or the assistance information. For example, theassistance information may include information for selecting the SLresource, and the assistance information may be generated based on theassistance information request.

Various embodiments of the present disclosure may be combined with eachother.

Hereinafter, device(s) to which various embodiments of the presentdisclosure can be applied will be described.

The various descriptions, functions, procedures, proposals, methods,and/or operational flowcharts of the present disclosure described inthis document may be applied to, without being limited to, a variety offields requiring wireless communication/connection (e.g., 5G) betweendevices.

Hereinafter, a description will be given in more detail with referenceto the drawings. In the following drawings/description, the samereference symbols may denote the same or corresponding hardware blocks,software blocks, or functional blocks unless described otherwise.

FIG. 17 shows a communication system 1, based on an embodiment of thepresent disclosure.

Referring to FIG. 17 , a communication system 1 to which variousembodiments of the present disclosure are applied includes wirelessdevices, Base Stations (BSs), and a network. Herein, the wirelessdevices represent devices performing communication using Radio AccessTechnology (RAT) (e.g., 5G New RAT (NR)) or Long-Term Evolution (LTE))and may be referred to as communication/radio/5G devices. The wirelessdevices may include, without being limited to, a robot 100 a, vehicles100 b-1 and 100 b-2, an eXtended Reality (XR) device 100 c, a hand-helddevice 100 d, a home appliance 100 e, an Internet of Things (IoT) device100 f, and an Artificial Intelligence (AI) device/server 400. Forexample, the vehicles may include a vehicle having a wirelesscommunication function, an autonomous vehicle, and a vehicle capable ofperforming communication between vehicles. Herein, the vehicles mayinclude an Unmanned Aerial Vehicle (UAV) (e.g., a drone). The XR devicemay include an Augmented Reality (AR)/Virtual Reality (VR)/Mixed Reality(MR) device and may be implemented in the form of a Head-Mounted Device(HMD), a Head-Up Display (HUD) mounted in a vehicle, a television, asmartphone, a computer, a wearable device, a home appliance device, adigital signage, a vehicle, a robot, etc. The hand-held device mayinclude a smartphone, a smartpad, a wearable device (e.g., a smartwatchor a smartglasses), and a computer (e.g., a notebook). The homeappliance may include a TV, a refrigerator, and a washing machine. TheIoT device may include a sensor and a smartmeter. For example, the BSsand the network may be implemented as wireless devices and a specificwireless device 200 a may operate as a BS/network node with respect toother wireless devices.

Here, wireless communication technology implemented in wireless devices100 a to 100 f of the present disclosure may include Narrowband Internetof Things for low-power communication in addition to LTE, NR, and 6G. Inthis case, for example, NB-IoT technology may be an example of Low PowerWide Area Network (LPWAN) technology and may be implemented as standardssuch as LTE Cat NB1, and/or LTE Cat NB2, and is not limited to the namedescribed above. Additionally or alternatively, the wirelesscommunication technology implemented in the wireless devices 100 a to100 f of the present disclosure may perform communication based on LTE-Mtechnology. In this case, as an example, the LTE-M technology may be anexample of the LPWAN and may be called by various names includingenhanced Machine Type Communication (eMTC), and the like. For example,the LTE-M technology may be implemented as at least any one of variousstandards such as 1) LTE CAT 0, 2) LTE Cat M1, 3) LTE Cat M2, 4) LTEnon-Bandwidth Limited (non-BL), 5) LTE-MTC, 6) LTE Machine TypeCommunication, and/or 7) LTE M, and is not limited to the name describedabove. Additionally or alternatively, the wireless communicationtechnology implemented in the wireless devices 100 a to 100 f of thepresent disclosure may include at least one of Bluetooth, Low Power WideArea Network (LPWAN), and ZigBee considering the low-powercommunication, and is not limited to the name described above. As anexample, the ZigBee technology may generate personal area networks (PAN)related to small/low-power digital communication based on variousstandards including IEEE 802.15.4, and the like, and may be called byvarious names.

The wireless devices 100 a to 100 f may be connected to the network 300via the BSs 200. An AI technology may be applied to the wireless devices100 a to 100 f and the wireless devices 100 a to 100 f may be connectedto the AI server 400 via the network 300. The network 300 may beconfigured using a 3G network, a 4G (e.g., LTE) network, or a 5G (e.g.,NR) network. Although the wireless devices 100 a to 100 f maycommunicate with each other through the BSs 200/network 300, thewireless devices 100 a to 100 f may perform direct communication (e.g.,sidelink communication) with each other without passing through theBSs/network. For example, the vehicles 100 b-1 and 100 b-2 may performdirect communication (e.g. Vehicle-to-Vehicle(V2V)/Vehicle-to-everything (V2X) communication). The IoT device (e.g.,a sensor) may perform direct communication with other IoT devices (e.g.,sensors) or other wireless devices 100 a to 100 f.

Wireless communication/connections 150 a, 150 b, or 150 c may beestablished between the wireless devices 100 a to 100 f/BS 200, or BS200/BS 200. Herein, the wireless communication/connections may beestablished through various RATs (e.g., 5G NR) such as uplink/downlinkcommunication 150 a, sidelink communication 150 b (or, D2Dcommunication), or inter BS communication (e.g. relay, Integrated AccessBackhaul (IAB)). The wireless devices and the BSs/the wireless devicesmay transmit/receive radio signals to/from each other through thewireless communication/connections 150 a and 150 b. For example, thewireless communication/connections 150 a and 150 b may transmit/receivesignals through various physical channels. To this end, at least a partof various configuration information configuring processes, varioussignal processing processes (e.g., channel encoding/decoding,modulation/demodulation, and resource mapping/demapping), and resourceallocating processes, for transmitting/receiving radio signals, may beperformed based on the various proposals of the present disclosure.

FIG. 18 shows wireless devices, based on an embodiment of the presentdisclosure.

Referring to FIG. 18 , a first wireless device 100 and a second wirelessdevice 200 may transmit radio signals through a variety of RATs (e.g.,LTE and NR). Herein, {the first wireless device 100 and the secondwireless device 200} may correspond to {the wireless device 100 x andthe BS 200} and/or {the wireless device 100 x and the wireless device100 x} of FIG. 17 .

The first wireless device 100 may include one or more processors 102 andone or more memories 104 and additionally further include one or moretransceivers 106 and/or one or more antennas 108. The processor(s) 102may control the memory(s) 104 and/or the transceiver(s) 106 and may beconfigured to implement the descriptions, functions, procedures,proposals, methods, and/or operational flowcharts disclosed in thisdocument. For example, the processor(s) 102 may process informationwithin the memory(s) 104 to generate first information/signals and thentransmit radio signals including the first information/signals throughthe transceiver(s) 106. The processor(s) 102 may receive radio signalsincluding second information/signals through the transceiver 106 andthen store information obtained by processing the secondinformation/signals in the memory(s) 104. The memory(s) 104 may beconnected to the processor(s) 102 and may store a variety of informationrelated to operations of the processor(s) 102. For example, thememory(s) 104 may store software code including commands for performinga part or the entirety of processes controlled by the processor(s) 102or for performing the descriptions, functions, procedures, proposals,methods, and/or operational flowcharts disclosed in this document.Herein, the processor(s) 102 and the memory(s) 104 may be a part of acommunication modem/circuit/chip designed to implement RAT (e.g., LTE orNR). The transceiver(s) 106 may be connected to the processor(s) 102 andtransmit and/or receive radio signals through one or more antennas 108.Each of the transceiver(s) 106 may include a transmitter and/or areceiver. The transceiver(s) 106 may be interchangeably used with RadioFrequency (RF) unit(s). In the present disclosure, the wireless devicemay represent a communication modem/circuit/chip.

The second wireless device 200 may include one or more processors 202and one or more memories 204 and additionally further include one ormore transceivers 206 and/or one or more antennas 208. The processor(s)202 may control the memory(s) 204 and/or the transceiver(s) 206 and maybe configured to implement the descriptions, functions, procedures,proposals, methods, and/or operational flowcharts disclosed in thisdocument. For example, the processor(s) 202 may process informationwithin the memory(s) 204 to generate third information/signals and thentransmit radio signals including the third information/signals throughthe transceiver(s) 206. The processor(s) 202 may receive radio signalsincluding fourth information/signals through the transceiver(s) 106 andthen store information obtained by processing the fourthinformation/signals in the memory(s) 204. The memory(s) 204 may beconnected to the processor(s) 202 and may store a variety of informationrelated to operations of the processor(s) 202. For example, thememory(s) 204 may store software code including commands for performinga part or the entirety of processes controlled by the processor(s) 202or for performing the descriptions, functions, procedures, proposals,methods, and/or operational flowcharts disclosed in this document.Herein, the processor(s) 202 and the memory(s) 204 may be a part of acommunication modem/circuit/chip designed to implement RAT (e.g., LTE orNR). The transceiver(s) 206 may be connected to the processor(s) 202 andtransmit and/or receive radio signals through one or more antennas 208.Each of the transceiver(s) 206 may include a transmitter and/or areceiver. The transceiver(s) 206 may be interchangeably used with RFunit(s). In the present disclosure, the wireless device may represent acommunication modem/circuit/chip.

Hereinafter, hardware elements of the wireless devices 100 and 200 willbe described more specifically. One or more protocol layers may beimplemented by, without being limited to, one or more processors 102 and202. For example, the one or more processors 102 and 202 may implementone or more layers (e.g., functional layers such as PHY, MAC, RLC, PDCP,RRC, and SDAP). The one or more processors 102 and 202 may generate oneor more Protocol Data Units (PDUs) and/or one or more Service Data Unit(SDUs) according to the descriptions, functions, procedures, proposals,methods, and/or operational flowcharts disclosed in this document. Theone or more processors 102 and 202 may generate messages, controlinformation, data, or information according to the descriptions,functions, procedures, proposals, methods, and/or operational flowchartsdisclosed in this document. The one or more processors 102 and 202 maygenerate signals (e.g., baseband signals) including PDUs, SDUs,messages, control information, data, or information according to thedescriptions, functions, procedures, proposals, methods, and/oroperational flowcharts disclosed in this document and provide thegenerated signals to the one or more transceivers 106 and 206. The oneor more processors 102 and 202 may receive the signals (e.g., basebandsignals) from the one or more transceivers 106 and 206 and acquire thePDUs, SDUs, messages, control information, data, or informationaccording to the descriptions, functions, procedures, proposals,methods, and/or operational flowcharts disclosed in this document.

The one or more processors 102 and 202 may be referred to ascontrollers, microcontrollers, microprocessors, or microcomputers. Theone or more processors 102 and 202 may be implemented by hardware,firmware, software, or a combination thereof. As an example, one or moreApplication Specific Integrated Circuits (ASICs), one or more DigitalSignal Processors (DSPs), one or more Digital Signal Processing Devices(DSPDs), one or more Programmable Logic Devices (PLDs), or one or moreField Programmable Gate Arrays (FPGAs) may be included in the one ormore processors 102 and 202. The descriptions, functions, procedures,proposals, methods, and/or operational flowcharts disclosed in thisdocument may be implemented using firmware or software and the firmwareor software may be configured to include the modules, procedures, orfunctions. Firmware or software configured to perform the descriptions,functions, procedures, proposals, methods, and/or operational flowchartsdisclosed in this document may be included in the one or more processors102 and 202 or stored in the one or more memories 104 and 204 so as tobe driven by the one or more processors 102 and 202. The descriptions,functions, procedures, proposals, methods, and/or operational flowchartsdisclosed in this document may be implemented using firmware or softwarein the form of code, commands, and/or a set of commands.

The one or more memories 104 and 204 may be connected to the one or moreprocessors 102 and 202 and store various types of data, signals,messages, information, programs, code, instructions, and/or commands.The one or more memories 104 and 204 may be configured by Read-OnlyMemories (ROMs), Random Access Memories (RAMs), Electrically ErasableProgrammable Read-Only Memories (EPROMs), flash memories, hard drives,registers, cash memories, computer-readable storage media, and/orcombinations thereof. The one or more memories 104 and 204 may belocated at the interior and/or exterior of the one or more processors102 and 202. The one or more memories 104 and 204 may be connected tothe one or more processors 102 and 202 through various technologies suchas wired or wireless connection.

The one or more transceivers 106 and 206 may transmit user data, controlinformation, and/or radio signals/channels, mentioned in the methodsand/or operational flowcharts of this document, to one or more otherdevices. The one or more transceivers 106 and 206 may receive user data,control information, and/or radio signals/channels, mentioned in thedescriptions, functions, procedures, proposals, methods, and/oroperational flowcharts disclosed in this document, from one or moreother devices. For example, the one or more transceivers 106 and 206 maybe connected to the one or more processors 102 and 202 and transmit andreceive radio signals. For example, the one or more processors 102 and202 may perform control so that the one or more transceivers 106 and 206may transmit user data, control information, or radio signals to one ormore other devices. The one or more processors 102 and 202 may performcontrol so that the one or more transceivers 106 and 206 may receiveuser data, control information, or radio signals from one or more otherdevices. The one or more transceivers 106 and 206 may be connected tothe one or more antennas 108 and 208 and the one or more transceivers106 and 206 may be configured to transmit and receive user data, controlinformation, and/or radio signals/channels, mentioned in thedescriptions, functions, procedures, proposals, methods, and/oroperational flowcharts disclosed in this document, through the one ormore antennas 108 and 208. In this document, the one or more antennasmay be a plurality of physical antennas or a plurality of logicalantennas (e.g., antenna ports). The one or more transceivers 106 and 206may convert received radio signals/channels etc. from RF band signalsinto baseband signals in order to process received user data, controlinformation, radio signals/channels, etc. using the one or moreprocessors 102 and 202. The one or more transceivers 106 and 206 mayconvert the user data, control information, radio signals/channels, etc.processed using the one or more processors 102 and 202 from the baseband signals into the RF band signals. To this end, the one or moretransceivers 106 and 206 may include (analog) oscillators and/orfilters.

FIG. 19 shows a signal process circuit for a transmission signal, basedon an embodiment of the present disclosure.

Referring to FIG. 19 , a signal processing circuit 1000 may includescramblers 1010, modulators 1020, a layer mapper 1030, a precoder 1040,resource mappers 1050, and signal generators 1060. An operation/functionof FIG. 19 may be performed, without being limited to, the processors102 and 202 and/or the transceivers 106 and 206 of FIG. 18 . Hardwareelements of FIG. 19 may be implemented by the processors 102 and 202and/or the transceivers 106 and 206 of FIG. 18 . For example, blocks1010 to 1060 may be implemented by the processors 102 and 202 of FIG. 18. Alternatively, the blocks 1010 to 1050 may be implemented by theprocessors 102 and 202 of FIG. 18 and the block 1060 may be implementedby the transceivers 106 and 206 of FIG. 18 .

Codewords may be converted into radio signals via the signal processingcircuit 1000 of FIG. 19 . Herein, the codewords are encoded bitsequences of information blocks. The information blocks may includetransport blocks (e.g., a UL-SCH transport block, a DL-SCH transportblock). The radio signals may be transmitted through various physicalchannels (e.g., a PUSCH and a PDSCH).

Specifically, the codewords may be converted into scrambled bitsequences by the scramblers 1010. Scramble sequences used for scramblingmay be generated based on an initialization value, and theinitialization value may include ID information of a wireless device.The scrambled bit sequences may be modulated to modulation symbolsequences by the modulators 1020. A modulation scheme may includepi/2-Binary Phase Shift Keying (pi/2-BPSK), m-Phase Shift Keying(m-PSK), and m-Quadrature Amplitude Modulation (m-QAM). Complexmodulation symbol sequences may be mapped to one or more transportlayers by the layer mapper 1030. Modulation symbols of each transportlayer may be mapped (precoded) to corresponding antenna port(s) by theprecoder 1040. Outputs z of the precoder 1040 may be obtained bymultiplying outputs y of the layer mapper 1030 by an N*M precodingmatrix W. Herein, N is the number of antenna ports and M is the numberof transport layers. The precoder 1040 may perform precoding afterperforming transform precoding (e.g., DFT) for complex modulationsymbols. Alternatively, the precoder 1040 may perform precoding withoutperforming transform precoding.

The resource mappers 1050 may map modulation symbols of each antennaport to time-frequency resources. The time-frequency resources mayinclude a plurality of symbols (e.g., a CP-OFDMA symbols and DFT-s-OFDMAsymbols) in the time domain and a plurality of subcarriers in thefrequency domain. The signal generators 1060 may generate radio signalsfrom the mapped modulation symbols and the generated radio signals maybe transmitted to other devices through each antenna. For this purpose,the signal generators 1060 may include Inverse Fast Fourier Transform(IFFT) modules, Cyclic Prefix (CP) inserters, Digital-to-AnalogConverters (DACs), and frequency up-converters.

Signal processing procedures for a signal received in the wirelessdevice may be configured in a reverse manner of the signal processingprocedures 1010 to 1060 of FIG. 19 . For example, the wireless devices(e.g., 100 and 200 of FIG. 18 ) may receive radio signals from theexterior through the antenna ports/transceivers. The received radiosignals may be converted into baseband signals through signal restorers.To this end, the signal restorers may include frequency downlinkconverters, Analog-to-Digital Converters (ADCs), CP remover, and FastFourier Transform (FFT) modules. Next, the baseband signals may berestored to codewords through a resource demapping procedure, apostcoding procedure, a demodulation processor, and a descramblingprocedure. The codewords may be restored to original information blocksthrough decoding. Therefore, a signal processing circuit (notillustrated) for a reception signal may include signal restorers,resource demappers, a postcoder, demodulators, descramblers, anddecoders.

FIG. 20 shows another example of a wireless device, based on anembodiment of the present disclosure. The wireless device may beimplemented in various forms according to a use-case/service (refer toFIG. 17 ).

Referring to FIG. 20 , wireless devices 100 and 200 may correspond tothe wireless devices 100 and 200 of FIG. 18 and may be configured byvarious elements, components, units/portions, and/or modules. Forexample, each of the wireless devices 100 and 200 may include acommunication unit 110, a control unit 120, a memory unit 130, andadditional components 140. The communication unit may include acommunication circuit 112 and transceiver(s) 114. For example, thecommunication circuit 112 may include the one or more processors 102 and202 and/or the one or more memories 104 and 204 of FIG. 18 . Forexample, the transceiver(s) 114 may include the one or more transceivers106 and 206 and/or the one or more antennas 108 and 208 of FIG. 18 . Thecontrol unit 120 is electrically connected to the communication unit110, the memory 130, and the additional components 140 and controlsoverall operation of the wireless devices. For example, the control unit120 may control an electric/mechanical operation of the wireless devicebased on programs/code/commands/information stored in the memory unit130. The control unit 120 may transmit the information stored in thememory unit 130 to the exterior (e.g., other communication devices) viathe communication unit 110 through a wireless/wired interface or store,in the memory unit 130, information received through the wireless/wiredinterface from the exterior (e.g., other communication devices) via thecommunication unit 110.

The additional components 140 may be variously configured according totypes of wireless devices. For example, the additional components 140may include at least one of a power unit/battery, input/output (I/O)unit, a driving unit, and a computing unit. The wireless device may beimplemented in the form of, without being limited to, the robot (100 aof FIG. 17 ), the vehicles (100 b-1 and 100 b-2 of FIG. 17 ), the XRdevice (100 c of FIG. 17 ), the hand-held device (100 d of FIG. 17 ),the home appliance (100 e of FIG. 17 ), the IoT device (100 f of FIG. 17), a digital broadcast terminal, a hologram device, a public safetydevice, an MTC device, a medicine device, a fintech device (or a financedevice), a security device, a climate/environment device, the AIserver/device (400 of FIG. 17 ), the BSs (200 of FIG. 17 ), a networknode, etc. The wireless device may be used in a mobile or fixed placeaccording to a use-example/service.

In FIG. 20 , the entirety of the various elements, components,units/portions, and/or modules in the wireless devices 100 and 200 maybe connected to each other through a wired interface or at least a partthereof may be wirelessly connected through the communication unit 110.For example, in each of the wireless devices 100 and 200, the controlunit 120 and the communication unit 110 may be connected by wire and thecontrol unit 120 and first units (e.g., 130 and 140) may be wirelesslyconnected through the communication unit 110. Each element, component,unit/portion, and/or module within the wireless devices 100 and 200 mayfurther include one or more elements. For example, the control unit 120may be configured by a set of one or more processors. As an example, thecontrol unit 120 may be configured by a set of a communication controlprocessor, an application processor, an Electronic Control Unit (ECU), agraphical processing unit, and a memory control processor. As anotherexample, the memory 130 may be configured by a Random Access Memory(RAM), a Dynamic RAM (DRAM), a Read Only Memory (ROM)), a flash memory,a volatile memory, a non-volatile memory, and/or a combination thereof.

Hereinafter, an example of implementing FIG. 20 will be described indetail with reference to the drawings.

FIG. 21 shows a hand-held device, based on an embodiment of the presentdisclosure. The hand-held device may include a smartphone, a smartpad, awearable device (e.g., a smartwatch or a smartglasses), or a portablecomputer (e.g., a notebook). The hand-held device may be referred to asa mobile station (MS), a user terminal (UT), a Mobile Subscriber Station(MSS), a Subscriber Station (SS), an Advanced Mobile Station (AMS), or aWireless Terminal (WT).

Referring to FIG. 21 , a hand-held device 100 may include an antennaunit 108, a communication unit 110, a control unit 120, a memory unit130, a power supply unit 140 a, an interface unit 140 b, and an I/O unit140 c. The antenna unit 108 may be configured as a part of thecommunication unit 110. Blocks 110 to 130/140 a to 140 c correspond tothe blocks 110 to 130/140 of FIG. 20 , respectively.

The communication unit 110 may transmit and receive signals (e.g., dataand control signals) to and from other wireless devices or BSs. Thecontrol unit 120 may perform various operations by controllingconstituent elements of the hand-held device 100. The control unit 120may include an Application Processor (AP). The memory unit 130 may storedata/parameters/programs/code/commands needed to drive the hand-helddevice 100. The memory unit 130 may store input/output data/information.The power supply unit 140 a may supply power to the hand-held device 100and include a wired/wireless charging circuit, a battery, etc. Theinterface unit 140 b may support connection of the hand-held device 100to other external devices. The interface unit 140 b may include variousports (e.g., an audio I/O port and a video I/O port) for connection withexternal devices. The I/O unit 140 c may input or output videoinformation/signals, audio information/signals, data, and/or informationinput by a user. The I/O unit 140 c may include a camera, a microphone,a user input unit, a display unit 140 d, a speaker, and/or a hapticmodule.

As an example, in the case of data communication, the I/O unit 140 c mayacquire information/signals (e.g., touch, text, voice, images, or video)input by a user and the acquired information/signals may be stored inthe memory unit 130. The communication unit 110 may convert theinformation/signals stored in the memory into radio signals and transmitthe converted radio signals to other wireless devices directly or to aBS. The communication unit 110 may receive radio signals from otherwireless devices or the BS and then restore the received radio signalsinto original information/signals. The restored information/signals maybe stored in the memory unit 130 and may be output as various types(e.g., text, voice, images, video, or haptic) through the I/O unit 140c.

FIG. 22 shows a vehicle or an autonomous vehicle, based on an embodimentof the present disclosure. The vehicle or autonomous vehicle may beimplemented by a mobile robot, a car, a train, a manned/unmanned AerialVehicle (AV), a ship, etc.

Referring to FIG. 22 , a vehicle or autonomous vehicle 100 may includean antenna unit 108, a communication unit 110, a control unit 120, adriving unit 140 a, a power supply unit 140 b, a sensor unit 140 c, andan autonomous driving unit 140 d. The antenna unit 108 may be configuredas a part of the communication unit 110. The blocks 110/130/140 a to 140d correspond to the blocks 110/130/140 of FIG. 20 , respectively.

The communication unit 110 may transmit and receive signals (e.g., dataand control signals) to and from external devices such as othervehicles, BSs (e.g., gNBs and road side units), and servers. The controlunit 120 may perform various operations by controlling elements of thevehicle or the autonomous vehicle 100. The control unit 120 may includean Electronic Control Unit (ECU). The driving unit 140 a may cause thevehicle or the autonomous vehicle 100 to drive on a road. The drivingunit 140 a may include an engine, a motor, a powertrain, a wheel, abrake, a steering device, etc. The power supply unit 140 b may supplypower to the vehicle or the autonomous vehicle 100 and include awired/wireless charging circuit, a battery, etc. The sensor unit 140 cmay acquire a vehicle state, ambient environment information, userinformation, etc. The sensor unit 140 c may include an InertialMeasurement Unit (IMU) sensor, a collision sensor, a wheel sensor, aspeed sensor, a slope sensor, a weight sensor, a heading sensor, aposition module, a vehicle forward/backward sensor, a battery sensor, afuel sensor, a tire sensor, a steering sensor, a temperature sensor, ahumidity sensor, an ultrasonic sensor, an illumination sensor, a pedalposition sensor, etc. The autonomous driving unit 140 d may implementtechnology for maintaining a lane on which a vehicle is driving,technology for automatically adjusting speed, such as adaptive cruisecontrol, technology for autonomously driving along a determined path,technology for driving by automatically setting a path if a destinationis set, and the like.

For example, the communication unit 110 may receive map data, trafficinformation data, etc. from an external server. The autonomous drivingunit 140 d may generate an autonomous driving path and a driving planfrom the obtained data. The control unit 120 may control the drivingunit 140 a such that the vehicle or the autonomous vehicle 100 may movealong the autonomous driving path according to the driving plan (e.g.,speed/direction control). In the middle of autonomous driving, thecommunication unit 110 may aperiodically/periodically acquire recenttraffic information data from the external server and acquiresurrounding traffic information data from neighboring vehicles. In themiddle of autonomous driving, the sensor unit 140 c may obtain a vehiclestate and/or surrounding environment information. The autonomous drivingunit 140 d may update the autonomous driving path and the driving planbased on the newly obtained data/information. The communication unit 110may transfer information about a vehicle position, the autonomousdriving path, and/or the driving plan to the external server. Theexternal server may predict traffic information data using AItechnology, etc., based on the information collected from vehicles orautonomous vehicles and provide the predicted traffic information datato the vehicles or the autonomous vehicles.

Claims in the present description can be combined in a various way. Forinstance, technical features in method claims of the present descriptioncan be combined to be implemented or performed in an apparatus, andtechnical features in apparatus claims can be combined to be implementedor performed in a method. Further, technical features in method claim(s)and apparatus claim(s) can be combined to be implemented or performed inan apparatus. Further, technical features in method claim(s) andapparatus claim(s) can be combined to be implemented or performed in amethod.

What is claimed is:
 1. A method for performing wireless communication bya first device, the method comprising: receiving, from a second device,an assistance information request including information related to apriority, information related to a number of subchannels for sidelinktransmission, and information related to a resource selection windowlocation; determining a preferred resource set or a non-preferredresource set for transmission of the second device, based on theassistance information request; transmitting, to the second devicethrough a physical sidelink control channel (PSCCH), first sidelinkcontrol information (SCI) including scheduling information for aphysical sidelink shared channel (PSSCH), wherein the first SCI includesinformation related to frequency resource assignment, informationrelated to time resource assignment, information related to ademodulation reference signal (DMRS) pattern, and information related tomodulation and coding scheme (MCS); and transmitting, to the seconddevice through the PSSCH, assistance information including the preferredresource set or the non-preferred resource set.
 2. The method of claim1, wherein a second SCI including the assistance information istransmitted through the PSSCH.
 3. The method of claim 1, wherein theassistance information request further includes information related to aresource reservation period.
 4. The method of claim 3, wherein, based onthe assistance information request including the information related tothe resource reservation period, the assistance information includinginformation related to at least one resource having the resourcereservation period is generated.
 5. The method of claim 1, wherein,based on the assistance information request including the informationrelated to the priority, the assistance information related to thepriority is generated.
 6. The method of claim 1, wherein, based on theassistance information request including the information related to theresource selection window location, the assistance information includinginformation related to at least one resource within the resourceselection window location is generated.
 7. The method of claim 1,wherein, based on the assistance information request including theinformation related to the number of subchannels for sidelinktransmission, the assistance information including information relatedto at least one resource having the number of subchannels is generated.8. The method of claim 1, wherein the assistance information requestfurther includes information related to a resource set type, and whereinthe resource set type represents whether the assistance informationrequest is a request for assistance information providing the preferredresource set or a request for assistance information providing thenon-preferred resource set.
 9. The method of claim 1, wherein, based onthe assistance information including the non-preferred resource set, aresource overlapping with the non-preferred resource set is excludedfrom a candidate resource set for transmission of the second devicedetermined based on sensing by the second device.
 10. The method ofclaim 1, wherein, based on the assistance information including thepreferred resource set, a resource for transmission of the second deviceis selected within the preferred resource set.
 11. The method of claim1, wherein a set of physical sidelink feedback channel (PSFCH) resourcesfor PSFCH transmission or reception including resource conflictinformation and a set of PSFCH resources for PSFCH transmission orreception including hybrid automatic repeat request (HARQ) feedbackinformation are configured, respectively.
 12. The method of claim 11,wherein a priority of the PSFCH transmission or reception including theHARQ feedback information is higher than a priority of the PSFCHtransmission or reception including the resource conflict information.13. The method of claim 1, wherein a priority related to transmission ofthe assistance information is configured for each resource pool.
 14. Afirst device adapted to perform wireless communication, the first devicecomprising: at least one transceiver; at least one processor; and atleast one memory connected to the at least one processor and storinginstructions that, based on being executed by the at least oneprocessor, perform operations comprising: receiving, from a seconddevice, an assistance information request including information relatedto a priority, information related to a number of subchannels forsidelink transmission, and information related to a resource selectionwindow location; determining a preferred resource set or a non-preferredresource set for transmission of the second device, based on theassistance information request; transmitting, to the second devicethrough a physical sidelink control channel (PSCCH), first sidelinkcontrol information (SCI) including scheduling information for aphysical sidelink shared channel (PSSCH), wherein the first SCI includesinformation related to frequency resource assignment, informationrelated to time resource assignment, information related to ademodulation reference signal (DMRS) pattern, and information related tomodulation and coding scheme (MCS); and transmitting, to the seconddevice through the PSSCH, assistance information including the preferredresource set or the non-preferred resource set.
 15. A processing deviceadapted to control a first device, the processing device comprising: atleast one processor; and at least one memory connected to the at leastone processor and storing instructions that, based on being executed bythe at least one processor, perform operations comprising: receiving,from a second device, an assistance information request includinginformation related to a priority, information related to a number ofsubchannels for sidelink transmission, and information related to aresource selection window location; determining a preferred resource setor a non-preferred resource set for transmission of the second device,based on the assistance information request; transmitting, to the seconddevice through a physical sidelink control channel (PSCCH), firstsidelink control information (SCI) including scheduling information fora physical sidelink shared channel (PSSCH), wherein the first SCIincludes information related to frequency resource assignment,information related to time resource assignment, information related toa demodulation reference signal (DMRS) pattern, and information relatedto modulation and coding scheme (MCS); and transmitting, to the seconddevice through the PSSCH, assistance information including the preferredresource set or the non-preferred resource set.
 16. The processingdevice of claim 15, wherein a second SCI including the assistanceinformation is transmitted through the PSSCH.
 17. The processing deviceof claim 15, wherein the assistance information request further includesinformation related to a resource reservation period, and wherein, basedon the assistance information request including the information relatedto the resource reservation period, the assistance information includinginformation related to at least one resource having the resourcereservation period is generated.
 18. The processing device of claim 15,wherein, based on the assistance information request including theinformation related to the priority, the assistance information relatedto the priority is generated.
 19. The processing device of claim 15,wherein, based on the assistance information request including theinformation related to the resource selection window location, theassistance information including information related to at least oneresource within the resource selection window location is generated. 20.The processing device of claim 15, wherein, based on the assistanceinformation request including the information related to the number ofsubchannels for sidelink transmission, the assistance informationincluding information related to at least one resource having the numberof subchannels is generated.